U.S. patent application number 17/622345 was filed with the patent office on 2022-08-11 for systems and methods of joint harq feedback for pdsch transmission over multiple trps.
The applicant listed for this patent is Telefonaktiebolaget LM Ericsson (publ). Invention is credited to Robert Baldemair, Mattias Frenne, Shiwei Gao, Siva Muruganathan.
Application Number | 20220256573 17/622345 |
Document ID | / |
Family ID | |
Filed Date | 2022-08-11 |
United States Patent
Application |
20220256573 |
Kind Code |
A1 |
Frenne; Mattias ; et
al. |
August 11, 2022 |
SYSTEMS AND METHODS OF JOINT HARQ FEEDBACK FOR PDSCH TRANSMISSION
OVER MULTIPLE TRPs
Abstract
Systems and methods for joint Hybrid Automatic Repeat Request
(HARQ) feedback for Physical Downlink Shared Channel (PDSCH)
transmission over multiple TRPs are provided. In some embodiments,
a method performed by a wireless device for enabling transmission
feedback includes: receiving a first Transport Block (TB) and a
second TB; and determining the first TB and the second TB based on
a Control Resource Set (CORESET) group identifier of a CORESET over
which a corresponding Downlink Control Information (DCI) scheduling
the TB is received. In this way, the New Radio (NR) Rel-15
procedure for type 1 HARQ codebook construction might be reused
with the same or minimum increase of HARQ feedback overhead with
semi-static HARQ-ACK codebook.
Inventors: |
Frenne; Mattias; (Uppsala,
SE) ; Baldemair; Robert; (Solna, SE) ; Gao;
Shiwei; (Nepean, CA) ; Muruganathan; Siva;
(Stittsville, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Telefonaktiebolaget LM Ericsson (publ) |
Stockholm |
|
SE |
|
|
Appl. No.: |
17/622345 |
Filed: |
June 25, 2020 |
PCT Filed: |
June 25, 2020 |
PCT NO: |
PCT/IB2020/056020 |
371 Date: |
December 23, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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62866408 |
Jun 25, 2019 |
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International
Class: |
H04W 72/12 20060101
H04W072/12; H04W 72/04 20060101 H04W072/04; H04L 1/18 20060101
H04L001/18; H04L 5/00 20060101 H04L005/00 |
Claims
1. A method performed by a wireless device for enabling
transmission feedback, the method comprising: receiving a first
Transport Block, TB, and a second TB in a Component Carrier, CC;
and determining the first TB and the second TB based on a Control
Resource Set, CORESET, group identifier of a CORESET over which a
corresponding Downlink Control Information, DCI, scheduling the TB
is received.
2. The method of claim 1 further comprising: prior to receiving the
first TB and the second TB, receiving a configuration with a set of
Physical Downlink Shared Channel, PDSCH-to-Hybrid Automatic Repeat
Request, HARQ-feedback timing, K1, values and/or a list of PDSCH
time domain resource allocations per slot in a serving cell.
3. The method of claim 1 further comprising: prior to receiving the
first TB and the second TB, receiving an indication to allocate two
entries, a first entry and a second entry, in a type-1 HARQ
codebook for each of the configured K1 values and each set of
overlapping PDSCH time domain resource assignments.
4. The method of claim 1 further comprising: mapping a HARQ-ACK bit
for the first TB to the first entry and a HARQ-ACK bit for the
second TB to the second entry in the Type-1 HARQ-ACK codebook
associated with a same K1 value and a same or overlapping PDSCH
time domain resource allocation.
5. The method of claim 1 further comprising: reporting the
constructed Type-1 HARQ ACK codebook.
6. The method of claim 1 wherein receiving the first TB and the
second TB comprises receiving in a slot the first TB scheduled by a
first DCI, from a first Transmission Reception Point, TRP,
represented by a first CORESET group identifier and the second TB
scheduled by a second DCI from a second TRP, represented by a
second CORESET group identifier, wherein the first and the second
TBs have a same or overlapping time domain resource allocation and
a same K1 value.
7. The method of claim 3 wherein receiving the indication to
allocate the two entries can be either explicit or implicit.
8. The method of claim 7 wherein receiving the indication to
allocate the two entries comprises receiving one or more of the
group consisting of: a higher layer parameter
maxNrofCodeWordsScheduledByDCI=2; a higher layer parameter
indicating joint HARQ ACK feedback and a configuration of two
CORESET groups each with a different group identifier value per
CORESET for HARQ-ACK reporting; and a configuration of one CORESET
group each with a same group identifier value per CORESET for
HARQ-ACK reporting.
9. The method of claim 1 wherein the first or the second entry is
filled with a Negative Acknowledgement, NACK, if the first or the
second TB is not correctly received, respectively.
10. The method of claim 1 wherein the transmitting may further
comprise transmitting one or two TBs scheduled by a single DCI.
11. The method of claim 1 wherein the first TB corresponds to
transport block 1 and the second TB corresponds to transport block
2 as indicated in the single DCI.
12. The method of claim 1 wherein the wireless device is a New
Radio, NR, User Equipment, UE.
13. The method of claim 1 wherein determining the first TB and the
second TB further comprises determining the first TB and the second
TB based on one or more of the group consisting of: a Demodulation
Reference Signal, DMRS, Code Division Multiplexing, CDM, group
identifier of one or more DMRS ports indicated in the corresponding
DCI scheduling the TB; a TB identifier indicated in the
corresponding DCI scheduling the TB; a Transmission Configuration
Indication, TCI, state identifier indicated in the corresponding
DCI scheduling the TB; a TCI state identifier of a CORESET over
which the corresponding DCI scheduling the TB is received; and a
scrambling identifier of a PDSCH carrying the TB.
14. A method performed by a base station for enabling transmission
feedback, the method comprising: transmitting, to a wireless
device, a first Transport Block, TB, and a second TB, where the
first TB and the second TB are determined based on a Control
Resource Set, CORESET, group identifier of a CORESET over which a
corresponding Downlink Control Information, DCI, scheduling the TB
is transmitted; and receiving, from the wireless device, a
constructed Type-1 Hybrid Automatic Repeat Request, HARQ, ACK
codebook.
15. The method of claim 14 further comprising: prior to
transmitting the first TB and the second TB, transmitting, to the
wireless device, a configuration with a set of Physical Downlink
Shared Channel, PDSCH-to-HARQ-feedback timing, K1, values and/or a
list of PDSCH time domain resource allocations per slot in a
serving cell.
16. The method of claim 14 further comprising: prior to
transmitting the first TB and the second TB, transmitting, to the
wireless device, an indication to allocate two entries, a first
entry and a second entry, in a type-1 HARQ codebook for each of the
configured K1 values and each set of overlapping PDSCH time domain
resource assignments.
17. The method of claim 14 wherein transmitting the first TB and
the second TB comprises transmitting in the slot the first TB
scheduled by a first DCI, from a first Transmission Reception
Point, TRP, represented by a first CORESET group identifier and the
second TB scheduled by a second DCI from a second TRP, represented
by a second CORESET group identifier, wherein the first and the
second TBs have a same or overlapping time domain resource
allocation and a same K1 value.
18. The method of claim 14 wherein transmitting the indication to
allocate the two entries can be either explicit or implicit.
19. The method of claim 18 wherein transmitting the indication to
allocate the two entries comprises: transmitting one or more of the
group consisting of: a higher layer parameter
maxNrofCodeWordsScheduledByDCI=2; a higher layer parameter
indicating joint HARQ ACK feedback and a configuration of two
CORESET groups each with a different group identifier value per
CORESET for HARQ-ACK reporting; a configuration of one CORESET
group each with a same group identifier value per CORESET for
HARQ-ACK reporting.
20. The method of claim 14 wherein the first or the second entry is
filled with a Negative Acknowledgement, NACK, if the first or the
second TB is not correctly received, respectively.
21. The method of claim 14 wherein the transmitting may further
comprise transmitting one or two TBs scheduled by a single DCI.
22. The method of claim 14 wherein the first TB corresponds to
transport block 1 and the second TB corresponds to transport block
2 as indicated in the single DCI.
23. The method of claim 14 wherein the base station is a New Radio,
NR, gNB.
24. The method of claim 14 wherein the first TB and the second TB
are further determined based on one or more of the group consisting
of: a Demodulation Reference Signal, DMRS, Code Division
Multiplexing, CDM, group identifier of one or more DMRS ports
indicated in the corresponding Downlink Control Information, DCI,
scheduling the TB; a TB identifier indicated in the corresponding
DCI scheduling the TB; a Transmission Configuration Indication,
TCI, state identifier indicated in the corresponding DCI scheduling
the TB; a TCI state identifier of a CORESET over which the
corresponding DCI scheduling the TB is received; and a scrambling
identifier of a PDSCH carrying the TB.
25. A wireless device for enabling transmission feedback, the
wireless device comprising: one or more processors; and memory
storing instructions executable by the one or more processors,
whereby the wireless device is operable to: receive a first
Transport Block, TB, and a second TB in a Component Carrier, CC;
and determine the first TB and the second TB based on a Control
Resource Set, CORESET, group identifier of a CORESET over which a
corresponding Downlink Control Information, DCI, scheduling the TB
is received.
26. (canceled)
27. A base station for enabling transmission feedback, the base
station comprising: one or more processors; and memory comprising
instructions to cause the base station to: transmit, to a wireless
device, a first Transport Block, TB, and a second TB, where the
first TB and the second TB are determined based on a Control
Resource Set, CORESET, group identifier of a CORESET over which a
corresponding Downlink Control Information, DCI, scheduling the TB
is transmitted; and receive, from the wireless device, a
constructed Type-1 Hybrid Automatic Repeat Request, HARQ,
codebook.
28. (canceled)
Description
RELATED APPLICATIONS
[0001] This application claims the benefit of provisional patent
application Ser. No. 62/866,408, filed Jun. 26, 2019, the
disclosure of which is hereby incorporated herein by reference in
its entirety.
TECHNICAL FIELD
[0002] The present disclosure relates to Hybrid Automatic Repeat
Request (HARQ) feedback.
BACKGROUND
[0003] New Radio (NR) uses Cyclic Prefix Orthogonal Frequency
Division Multiplexing (CP-OFDM) in both downlink (i.e., from a
network node, New Radio Base Station (gNB), or base station, to a
User Equipment (UE)) and uplink (i.e., from UE to gNB). Discrete
Fourier Transform (DFT) spread OFDM is also supported in the
uplink. In the time domain, NR downlinks and uplinks are organized
into equally-sized subframes of 1 ms each. A subframe is further
divided into multiple slots of equal duration. The slot length
depends on subcarrier spacing. For subcarrier spacing of
.DELTA.f=15 kHz, there is only one slot per subframe and each slot
consists of 14 OFDM symbols.
[0004] Data scheduling in NR is typically in slot basis. An example
is shown in FIG. 1 with a 14-symbol slot, where the first two
symbols contain Physical Downlink Control Channel (PDCCH) and the
rest contains physical shared data channel, either Physical
Downlink Shared Channel (PDSCH) or Physical Uplink Shared Channel
(PUSCH).
[0005] Different subcarrier spacing values are supported in NR. The
supported subcarrier spacing values (also referred to as different
numerologies) are given by .DELTA.f=(15.times.2.sup..mu.) kHz where
.mu..di-elect cons.0, 1, 2, 3, 4. .DELTA.f=15 kHz is the basic
subcarrier spacing. The slot durations at different subcarrier
spacings is given by
1 2 .mu. .times. .times. ms . ##EQU00001##
[0006] In the frequency domain, a system bandwidth is divided into
resource blocks (RBs), each corresponding to 12 contiguous
subcarriers. The RBs are numbered starting with 0 from one end of
the system bandwidth. The basic NR physical time-frequency resource
grid is illustrated in FIG. 2, where only one Resource Block (RB)
within a 14-symbol slot is shown. One OFDM subcarrier during one
OFDM symbol interval forms one Resource Element (RE).
[0007] Downlink transmissions are dynamically scheduled, i.e., in
each slot, the gNB transmits Downlink Control Information (DCI)
over the PDCCH about which UE data is to be transmitted to and
which RBs in the current downlink slot the data is transmitted on.
The UE data are carried on PDSCH.
[0008] There are two DCI formats defined for scheduling PDSCH in
NR, i.e., DCI format 1_0 and DCI format 1_1. DCI format 1-0 has a
smaller size than DCI 1_1 and can be used when a UE is not fully
connected to the network while DCI format 1_1 can be used for
scheduling Multiple-Input-Multiple-Output (MIMO) transmissions with
2 Transport Blocks (TBs).
[0009] QCL and TCI states: Several signals can be transmitted from
different antenna ports of a same base station antenna. When
received at a UE, these signals can have the same large-scale
properties, for instance in terms of Doppler shift and Doppler
spread, average delay spread, or average delay. These antenna ports
are then said to be Quasi Co-Located (QCL). In general, two quasi
co-located antenna ports may not necessarily be physically
co-located.
[0010] If the UE knows that two antenna ports are QCL with respect
to a certain parameter (e.g., Doppler spread), the UE can estimate
that parameter based on one of the antenna ports and use that
estimate when receiving from the other antenna port. Typically, the
first antenna port is represented by a measurement reference signal
such as a Channel State Information Reference Signal (CSI-RS) or
Synchronization Signal Block (SSB) (known as source RS) and the
second antenna port is a Demodulation Reference Signal (DMRS)
(known as target RS).
[0011] For instance, if antenna ports A and B are QCL with respect
to average delay, the UE can estimate the average delay from the
signal received from antenna port A (known as the source reference
signal (RS)) and assume that the signal received from antenna port
B (target RS) has the same average delay. This is useful for
demodulation since the UE can know beforehand the properties of the
channel when trying to measure the channel utilizing the DMRS,
which may help the UE in for instance selecting an appropriate
channel estimation filter.
[0012] Information about what assumptions can be made regarding QCL
is signaled to the UE from the network. In NR, four types of QCL
relations between a transmitted source RS and transmitted target RS
were defined: [0013] Type A: {Doppler shift, Doppler spread,
average delay, delay spread} [0014] Type B: {Doppler shift, Doppler
spread} [0015] Type C: {average delay, Doppler shift} [0016] Type
D: {Spatial Rx parameter}
[0017] QCL type D was introduced to facilitate beam management with
analog beamforming at higher carrier frequencies (e.g., 30 GHz) and
is known as spatial QCL. There is currently no strict definition of
spatial QCL, but the understanding is that if two transmitted
antenna ports are spatially QCL, the UE can use the same Rx beam to
receive them. Note that for beam management, the discussion mostly
revolves around QCL Type D, but it is also necessary to convey a
Type A QCL relation for the RSs to the UE so that it can estimate
all the relevant large-scale parameters.
[0018] Typically, this is achieved by configuring the UE with a
CSI-RS for tracking (TRS) for time/frequency offset estimation. To
be able to use any QCL reference, the UE would have to receive it
with a sufficiently good Signal to Interference Plus Noise Ratio
(SINR). In many cases, this means that the TRS has to be
transmitted in a suitable beam to a certain UE.
[0019] To introduce dynamics in beam and Transmission Reception
Point (TRP) selection, the UE can be configured through Radio
Resource Control (RRC) signalling with N Transmission Configuration
Indication (TCI) states, where Nis up to 128 in Frequency Range 2
(FR2) and up to 8 in FR1, depending on UE capability.
[0020] Each TCI state contains QCL information, i.e., one or two
source Downlink (DL) RSs, each source RS associated with a QCL
type. For example, a TCI state contains a pair of reference
signals, each associated with a QCL type, e-g- two different
CSI-RSs {CSI-RS1, CSI-RS2} are configured in the TCI state as
{qcl-Type1,qcl-Type2}={Type A, Type D}. It means the UE can derive
Doppler shift, Doppler spread, average delay, delay spread from
CSI-RS1 and Spatial Rx parameter (i.e., the RX beam to use) from
CSI-RS2.
[0021] Each of the N states in the list of TC states can be
interpreted as a list of N possible beams transmitted from the
network or a list of N possible TRPs used by the network to
communicate with the UE.
[0022] A first list of available TCI states is configured for
PDSCH, and a second list for PDCCH contains pointers, known as TCI
State IDs, to a subset of the TCI states configured for PDSCH. The
network then activates one TCI state for PDCCH (i.e., provides a
TCI for PDCCH) and up to eight active TCI states for PDSCH. The
number of active TCI states the UE supports is a UE capability, but
the maximum is eight. The TCI state(s) used for a PDSCH is
dynamically indicated in DCI 1_1.
[0023] Each configured TCI state contains parameters for the quasi
co-location associations between source reference signals (CSI-RS
or Synchronization Signal Block (SSB)) and target reference signals
(e.g., PDSCH/PDCCH DMRS ports). TCI states are also used to convey
QCL information for the reception of CSI-RS.
[0024] CORESET and Search Space: A PDCCH consists of one or more
Control-Channel Elements (CCEs) as indicated in Table 1 below. A
CCE consists of 6 Resource-Element Groups (REGs) where a REG equals
one RB during one OFDM symbol.
TABLE-US-00001 TABLE 1 NR supported PDCCH aggregation levels.
Aggregation level Number of CCEs 1 1 2 2 4 4 8 8 16 16
[0025] A set of PDCCH candidates for a UE to monitor is defined in
terms of PDCCH search space sets. A search space set can be a
Common Search Space (CSS) set or a UE Specific Search Space (USS)
set. A UE can be configured with up to 10 sets of search spaces per
bandwidth part for monitoring PDCCH candidates.
[0026] A search space set is defined over a Control Resource Set
(CORESET). A CORESET consists of N.sub.RB.sup.CORESET resource
blocks in the frequency domain and N.sub.symb.sup.CORESET.di-elect
cons.{1,2,3} consecutive OFDM symbols in the time domain. In NR
Rel-15, a UE can be configured with up to 3 CORESETs per bandwidth
part. For each CORESET, a UE is configured by Radio Resource
Control (RRC) signaling with CORESET Information Element (IE),
which includes the following [0027] a CORESET index p,
0.ltoreq.p<12; [0028] a DM-RS scrambling sequence initialization
value; [0029] a precoder granularity for a number of REGs in the
frequency domain where the UE can assume use of a same DM-RS
(DeModulation Reference Signal) precoder; [0030] a number of
consecutive symbols; [0031] a set of resource blocks; [0032]
CCE-to-REG mapping parameters; [0033] a list of up to 64 TCI-States
can be configured in a CORESET p. These TCI states are used to
provide QCL relationships between the source DL RS(s) in one RS Set
in the TCI State and the PDCCH DMRS ports (i.e., for DMRS ports for
PDCCHs received in one of the search spaces defined over CORESET
p). The source DL RS(s) can either be a CSI-RS or SSB; [0034] an
indication for a presence or absence of a transmission
configuration indication (TCI) field for DCI format 1_1 transmitted
by a PDCCH in CORESET p.
[0035] For each search space set, a UE is configured with the
following: [0036] a search space set index s, 0.ltoreq.s<40
[0037] an association between the search space set s and a CORESET
p [0038] a PDCCH monitoring periodicity of k, slots and a PDCCH
monitoring offset of o.sub.s slots [0039] a PDCCH monitoring
pattern within a slot, indicating first symbol(s) of the CORESET
within a slot for PDCCH monitoring [0040] a duration of
T.sub.s<k.sub.s slots indicating a number of slots that the
search space set s exists [0041] a number of PDCCH candidates
M.sub.s.sup.(L) per CCE aggregation level L [0042] an indication
that search space set s is either a CSS set or a USS set [0043] DCI
formats to monitoring
[0044] For search space set s, the UE determines that a PDCCH
monitoring occasion(s) exists in a slot with slot number
n.sub.s,f.sup..mu. in a frame with frame number n.sub.f if
(n.sub.fN.sub.slot.sup.frame,.mu.+n.sub.s,f.sup..mu.-o.sub.s)mod
k.sub.s=0. The UE monitors the PDCCH for search space set s for
T.sub.s consecutive slots, starting from slot n.sub.s,f.sup..mu.,
and does not monitor the PDCCH for search space set s for the next
k.sub.s-T.sub.s consecutive slots.
[0045] A UE first detects and decodes the PDCCH and if the decoding
is successful, it then decodes the corresponding PDSCH based on the
decoded control information in the PDCCH. When a PDSCH is
successfully decoded, the HARQ (Hybrid ARQ) ACK is sent to the gNB
over the Physical Uplink Control Channel (PUCCH). Otherwise, a HARQ
Negative Acknowledgement (NACK) is sent to the gNB over the PUCCH
so that data can be retransmitted to the UE. If the PUCCH overlaps
with a PUSCH transmission, HARQ feedback can also be conveyed on
the PUSCH.
[0046] Uplink data transmissions are also dynamically scheduled
using the PDCCH. Similar to downlink, a UE first decodes uplink
grants in the PDCCH and then transmits data over the PUSCH based
the decoded control information in the uplink grant such as
modulation order, coding rate, uplink resource allocation, etc.
[0047] DCI format 1_1 is used for the scheduling of the PDSCH in
one cell. The following information is transmitted by means of the
DCI format 1-1 with a Cyclic Redundancy Check (CRC) scrambled by
Cell-Radio Network Temporary Identifier (C-RNTI) or Configured
Scheduling-Radio Network Temporary Identifier (CS-RNTI) or
Modulation and Coding Scheme (MCS)-C-RNTI: [0048] Identifier for
DCI formats [0049] Carrier indicator [0050] Bandwidth part
indicator [0051] Frequency domain resource assignment [0052] Time
domain resource assignment (TDRA)-0, 1, 2, 3, or 4 bits as defined
in Subclause 5.1.2.1 of 3GPP TS 38.214. The bit width for this
field is determined as .left brkt-top.log.sub.2(I).right brkt-bot.
bits, where I is the number of entries in the higher layer
parameter pdsch-TimeDomainAllocationList if the higher layer
parameter is configured; otherwise I is the number of entries in
the default table. [0053] Virtual Resource Block (VRB)-to-Physical
Resource Block (PRB) mapping [0054] PRB bundling size indicator
[0055] Rate matching indicator [0056] Zero Power (ZP) CSI-RS
trigger
[0057] For transport block 1: [0058] Modulation and coding
scheme--5 bits (I.sub.MCS) [0059] New data indicator (NDI)--1 bit
[0060] Redundancy version--2 bits (rv.sub.id)
[0061] For transport block 2 (only present if
maxNrofCodeWordsScheduledByDCI equals 2): [0062] Modulation and
coding scheme--5 bits (I.sub.MCS) [0063] New data indicator
(NDI)--1 bit [0064] Redundancy version--2 bits (rv.sub.id) [0065]
HARQ process number [0066] Downlink assignment index (DAI) [0067]
Transmit Power Control (TPC) command for scheduled PUCCH [0068]
PUCCH resource indicator (PRI) [0069] PDSCH-to-HARQ_feedback timing
indicator (K1)--0, 1, 2, or 3 bits as defined in Subclause 9.2.3 of
3GPP TS 38.213. The bit width for this field is determined as .left
brkt-top.log.sub.2(I).right brkt-bot. bits, where I is the number
of entries in the higher layer parameter dl-DataToUL-ACK. [0070]
Antenna port(s)--4, 5, or 6 bits as defined by Tables
7.3.1.2.2-1/2/3/4 of 3GPP TS38.212 [0071] Transmission
configuration indication (TCI)--0 bit if higher layer parameter
tci-PresentInDCI is not enabled; otherwise 3 bits as defined in
Subclause 5.1.5 of 3GPP TS38.214. [0072] Sounding Reference Signal
request [0073] Code Block Group (CBG) transmission information
[0074] CBG flushing out information [0075] DMRS sequence
initialization--1 bit.
[0076] PDSCH Resource Allocation in Time Domain
[0077] When the UE is scheduled to receive PDSCH by a DCI, the Time
domain resource assignment (TDRA) field value m of the DCI provides
a row index m+1 to an allocation table. The determination of the
used resource allocation table is defined in sub-clause 5.1.2.1.1
of 3GPP TS38.214 v15.5.0, where either a default PDSCH time domain
allocation A, B or C according to tables 5.1.2.1.1-2, 5.1.2.1.1-3,
5.1.2.1.1-4 and 5.1.2.1.1-5 is applied, or the higher layer
configured parameter pdsch-TimeDomainAllocationList in either
pdsch-ConfigCommon or pdsch-Config is applied. Table 5.1.2.1.1-2 of
3GPP TS38.214 v15.5.0 is copied below.
TABLE-US-00002 TABLE 5.1.2.1.1-2 Default PDSCH time domain resource
allocation A for normal CP Row dmrs-TypeA- PDSCH index Position
mapping type K.sub.0 S L 1 2 Type A 0 2 12 3 Type A 0 3 11 2 2 Type
A 0 2 10 3 Type A 0 3 9 3 2 Type A 0 2 9 3 Type A 0 3 8 4 2 Type A
0 2 7 3 Type A 0 3 6 5 2 Type A 0 2 5 3 Type A 0 3 4 6 2 Type B 0 9
4 3 Type B 0 10 4 7 2 Type B 0 4 4 3 Type B 0 6 4 8 2, 3 Type B 0 5
7 9 2, 3 Type B 0 5 2 10 2, 3 Type B 0 9 2 11 2, 3 Type B 0 12 2 12
2, 3 Type A 0 1 13 13 2, 3 Type A 0 1 6 14 2, 3 Type A 0 2 4 15 2,
3 Type B 0 4 7 16 2, 3 Type B 0 8 4
[0078] The indexed row defines the slot offset K0, the start symbol
S, and the allocation length L in case that a default table is
used, and the PDSCH mapping type to be assumed in the PDSCH
reception. Either Type A (i.e., slot based PDSCH transmission) or
Type B (i.e., mini-slot based PDSCH transmission) may be indicated.
In case that pdsch-TimeDomainAllocationList is configured, the
pdsch-TimeDomainAllocationList contains a list of PDSCH-Time Domain
Resource Allocation Information Elements (IEs) as shown below,
where the start symbol S and the allocation length L is jointly
encoded in startSymbolAndLength as the start and length indicator
SLIV.
TABLE-US-00003 PDSCH-TimeDomainResourceAllocation ::= SEQUENCE { k0
INTEGER(0..32) mappingType ENUMERATED {typeA, typeB},
startSymbolAndLength INTEGER (0..127) }
[0079] The valid S and L values are shown in the table below.
TABLE-US-00004 TABLE 5.1.2.1-1 Valid S and L combinations (3gpp
TS38.214 v15.5.0) PDSCH mapping Normal cyclic prefix Extended
cyclic prefix type S L S + L S L S + L Type A {0, 1, 2, 3} {3, . .
. , 14} {3, . . . , 14} {0, 1, 2, 3} {3, . . . , 12} {3, . . . ,
12} (Note 1) (Note 1) Type B {0, . . . , 12} {2, 4, 7} {2, . . . ,
14} {0, . . . , 10} {2, 4, 6} {2, . . . , 12} Note 1: S = 3 is
applicable only if dmrs-TypeA-Position = 3
Note that for Type A PDSCH, the TDRAs in the
pdsch-TimeDomainAllocationList or the default table are overlapping
and only one PDSCH can be scheduled in a slot per cell in NR
Release 15. For Type B PDSCH, the TDRAs in the
pdsch-TimeDomainAllocationList or the default table may be
non-overlapping and thus more than one PDSCH may be scheduled in a
slot. FIG. 3 shows some examples, where in FIG. 3D two type B
PDSCHs are scheduled in a slot.
[0080] NR MIMO Data Transmission: NR data transmission over
multiple MIMO layers is shown in FIG. 4. Depending on the total
number of MIMO layers or the rank, either one Codeword (CW) or two
codewords are used. In NR Release-15, one codeword is used when the
total number of layers is equal to or less than 4, two codewords
are used when the number of layers is more than 4. Each codeword
contains the encoded data bits of a Transport Block (TB). After bit
level scrambling, the scrambled bits are mapped to complex-valued
modulation symbols d.sup.(q)(0), . . . , d.sup.(q)
(M.sub.symb.sup.(q)-1) for codeword q, q.di-elect cons.(0,1). The
complex-valued modulation symbols are then mapped onto the layers
x(i)=[x.sup.(0)(i) . . . x.sup.(v-1)(i)].sup.T, i=0, 1, . . . ,
M.sub.symb.sup.layer-1, according to Table 7.3.1.3-1 of 3GPP TS
38.211 v15.5.0.
[0081] For the purpose of demodulation, a demodulation reference
signal (DMRS), also referred to as a DMRS port, is transmitted
along each data layer. The block of vectors [x.sup.(0)(i) . . .
x.sup.(v-1)(i)].sup.T, i=0, 1, . . . , M.sub.symb.sup.layer-1 shall
be mapped to DMRS antenna ports according to
[ y ( p 0 ) .function. ( i ) y ( p v - 1 ) .function. ( i ) ] = [ x
( 0 ) .function. ( i ) x ( v - 1 ) .function. ( i ) ]
##EQU00002##
where i=0, 1, . . . , M.sub.symb.sup.ap-1,
M.sub.symb.sup.ap=M.sub.symb.sup.layer. The set of DMRS antenna
ports {p.sub.0, . . . , p.sub.v-1} and port to layer mapping are
dynamically indicated in DCI according to Tables 7.3.1.2.2-1/2/3/4
in 3GPP TS 38.212 v15.5.0.
[0082] The maximum number of TBs or codewords that can be scheduled
by DCI format 1-1 is configured by a higher layer parameter
maxNrofCodeWordsScheduledByDCI. Using this parameter, either 1 or 2
codewords can be configured. In case the higher layer parameter
maxNrofCodeWordsScheduledByDCI indicates that two codeword
transmission is enabled, then one of the two transport blocks is
disabled by DCI format 1-1 if I.sub.MCS=26 and if rv.sub.id=1 for
the corresponding transport block, where I.sub.MCS is the MCS
(modulation and coding scheme) index and rv.sub.id is the
redundancy version, both indicated in DCI 1_1. If both transport
blocks are enabled, transport block 1 and 2 are mapped to codeword
0 and 1 respectively. If only one transport block is enabled, then
the enabled transport block is always mapped to the first
codeword.
[0083] DMRS Code Division Multiplexing (CDM) groups: The mapping of
DMRS to resource elements is configurable in both frequency and
time domain. There are two mapping types in the frequency domain,
i.e., configuration type 1 or type 2. For each OFDM symbol
configured for DMRS, there are two Code Division Multiplexing (CDM)
groups for Type 1 and three CDM groups for Type 2 DMRS. An example
is shown in FIG. 5, where one front-loaded DMRS symbol is
configured.
[0084] DMRS ports to CDM group mappings are shown in Table 2 and
Table 3 for configuration type 1 and type 2, respectively.
TABLE-US-00005 TABLE 2 PDSCH DMRS port to CDM group mapping,
configuration type 1. p CDM group A 1000 0 1001 0 1002 1 1003 1
1004 0 1005 0 1006 1 1007 1
TABLE-US-00006 TABLE 3 PDSCH DMRS port to CDM group mapping,
configuration type 2. p CDM group 2 1000 0 1001 0 1002 1 1003 1
1004 2 1005 2 1006 0 1007 0 1008 1 1009 1 1010 2 1011 2
[0085] NR HARQ ACK/NACK feedback over PUCCH: When receiving a PDSCH
in the downlink from a serving gNB at slot n, a UE feeds back a
Hybrid Automatic Repeat Request (HARQ) ACK at slot n+k over a PUCCH
(Physical Uplink Control Channel) resource in the uplink to the gNB
if the PDSCH is decoded successfully, otherwise, the UE sends a
HARQ NACK at slot n+k to the gNB to indicate that the PDSCH is not
decoded successfully. If two TBs are carried by the PDSCH, then a
HARQ ACK/NACK is reported for each TB so that if one TB is not
decoded successfully, only that TB needs to be retransmitted by the
gNB. Spatial bundling can be configured, in which case the logical
AND of the decoding states of TB1 and TB2 is fed back. k is also
referred to as K.sub.1 in 3GPP specifications.
[0086] For DCI format 1-0, k is indicated by a 3-bit
PDSCH-to-HARQ-timing-indicator field. For DCI format 1-1, k is
indicated either by a 3-bit PDSCH-to-HARQ-timing-indicator field,
if present, or by higher layer through Radio Resource Control (RRC)
signaling.
[0087] If Code Block Group (CBG) transmission is configured, a HARQ
ACK/NACK for each CBG in a TB is reported instead.
[0088] In case of carrier aggregation (CA) with multiple component
carriers (CCs) and/or Time Division Duplexing (TDD) operation,
multiple aggregated HARQ ACK/NACK bits need to be sent in a single
PUCCH resource.
[0089] In NR, up to four PUCCH resource sets can be configured to a
UE. A PUCCH resource set with pucch-ResourceSetId=0 can have up to
32 PUCCH resources while for PUCCH resource sets with
pucch-ResourceSetId=1 to 3, each set can have up to 8 PUCCH
resources. A UE determines the PUCCH resource set in a slot based
on the number of aggregated UCI (Uplink Control Information) bits
to be sent in the slot. The UCI bits consist of HARQ ACK/NACK,
scheduling request (SR), and channel state information (CSI)
bits.
[0090] If the UE transmits O.sub.UCI UCI information bits, the UE
determines a PUCCH resource set to be [0091] a first set of PUCCH
resources with pucch-ResourceSetId=0 if O.sub.UCI.ltoreq.2
including 1 or 2 HARQ-ACK information bits and a positive or
negative SR on one SR transmission occasion if transmission of
HARQ-ACK information and SR occurs simultaneously, or [0092] a
second set of PUCCH resources with pucch-ResourceSetId=1, if
provided by higher layers, if 2<O.sub.UCI.ltoreq.N.sub.2, or
[0093] a third set of PUCCH resources with pucch-ResourceSetId=2,
if provided by higher layers, if
N.sub.2<O.sub.UCI.ltoreq.N.sub.3, or [0094] a fourth set of
PUCCH resources with pucch-ResourceSetId=3, if provided by higher
layers, if N.sub.3<O.sub.UCI.ltoreq.1706.
[0095] Where N.sub.1<N.sub.2<N.sub.3 are provided by higher
layers.
[0096] For a PUCCH transmission with HARQ-ACK information, a UE
determines a PUCCH resource after determining a PUCCH resource set.
The PUCCH resource determination is based on a 3-bit PUCCH resource
indicator (PRI) field in DCI format 1_0 or DC format 1_1.
[0097] If more than one DCI format 1_0 or 1_1 are received in the
case of CA and/or Time Division Duplexing (TDD), the PUCCH resource
determination is based on a PUCCH resource indicator (PRI) field in
the last DCI format 1_0 or DCI format 1-1 among the multiple
received DCI format 1_0 or DCI format 1-1 that the UE detects. The
multiple received DCI format 1_0 or DCI format 1_1 has a value of a
PDSCH-to-HARQ_feedback timing indicator field indicating a same
slot for the PUCCH transmission. For PUCCH resource determination,
detected DCI formats are first indexed in an ascending order across
serving cells indexes for a same PDCCH monitoring occasion and are
then indexed in an ascending order across PDCCH monitoring occasion
indexes.
[0098] The 3 bit PRI field maps to a PUCCH resource in a set of
PUCCH resources with a maximum of eight PUCCH resources. For the
first set of PUCCH resources with pucch-ResourceSetId=0 and when
the number of PUCCH resources, R.sub.PUCCH, in the set is larger
than eight, the UE determines a PUCCH resource with index
r.sub.PUCCH, 0.ltoreq.r.sub.PUCCH.ltoreq.R.sub.PUCCH-1, for
carrying HARQ-ACK information in response to detecting a last DCI
format 1_0 or DCI format 1_1 in a PDCCH reception, among DCI
formats 1_0 or DCI formats 1_1 the UE received with a value of the
PDSCH-to-HARQ_feedback timing indicator field indicating a same
slot for the PUCCH transmission, as
r PUCCH = { n CCE , p R PUCCH / 8 N CCE , p + .DELTA. PRI R PUCCH 8
if .times. .times. .DELTA. PRI < R PUCCH .times. mod .times. 8 n
CCE , p R PUCCH / 8 N CCE , p + .DELTA. PRI R PUCCH 8 + R PUCCH
.times. mod .times. 8 if .times. .times. .DELTA. PRI .gtoreq. R
PUCCH .times. mod .times. 8 } ##EQU00003##
where N.sub.CCE,p is a number of CCEs in CORESET p of the PDCCH
reception for the DCI format 1_0 or DCI format 1_1 as described in
Subclause 10.1 of 3gpp TS38.213 v15.4.0, n.sub.CCE,p is the index
of a first CCE for the PDCCH reception, and .DELTA..sub.PRI is a
value of the PUCCH resource indicator field in the DCI format 1_0
or DCI format 1_1.
[0099] NR Rel-15 supports two types of HARQ codebooks, i.e.,
semi-static (type 1) and dynamic (type 2) codebooks, for HARQ
ACK/NACK multiplexing for multiple PDSCHs of one or more CCs. A UE
can be configured to use either one of the codebooks for HARQ
ACK/NACK feedback.
[0100] NR Type-1 HARQ-ACK codebook determination: HARQ codebook
(CB) size in time (DL association set) is determined based on the
configured set of HARQ-ACK timings K1, and semi-static configured
TDD pattern in case of TDD.
[0101] An example is shown in FIG. 6 for a TDD pattern with a set
of K1 from 1 to 5 and a configured time-domain resource allocation
table or the pdsch-TimeDomainAllocationList without non-overlapping
PDSCH TDRA allocation, i.e., only one PDSCH can be scheduled in a
slot. In this case, there are 5 entries in the HARQ codebook, one
for each K1 value. For slots without PDSCH transmission or slots
where PDCCH for PDSCH scheduling is not detected by a UE, the
corresponding entry in the codebook is filled with NACK ("N" shown
in the figure). For slots in which PDSCH is scheduled, the
corresponding entry is filled with either ACK or NACK depending on
whether the PDSCH is successfully decoded or not ("X" shown in the
figure).
[0102] If UE supports reception of more than one unicast PDSCH per
slot, one HARQ codebook entry for each non-overlapping time-domain
resource allocation in the pdsch-symbolAllocation table is reserved
per slot; otherwise one HARQ entry is reserved per slot.
[0103] In case of MIMO with up to two codewords, an additional
entry is added for each K1 value. In case of multiple CCs,
additional entries in the HARQ codebook are added for each CC. In
component carrier dimension, HARQ codebook size is given by
configured number of DL cells and the max number of HARQ feedback
bits based on configuration per DL cell (e.g., MIMO, spatial
bundling, configured number of Code Block Groups (CBGs) per TB). An
example is shown in FIG. 7, where a semi-static HARQ codebook for a
UE is configured with three cells, i.e., cells 1 to 3. Cell 1 is
configured with up to 2 TBs per PDSCH, cell 2 with 1 TB per PDSCH,
and cell 3 with 1 TB and 4 CBG. For each K1 value, the UE needs to
feedback 7 bits, i.e., 2 bits for cell 1, 1 bit for cell 2, and 4
bits for cell 3 (not considering potential multiple entries per
slot based on the pdsch-symbolAllocation table). The rows and
columns shown in the figure are for illustration purposes; the
actual feedback is a single bit vector by arranging the bits in
certain order.
[0104] Non-coherent Joint Transmission (NC-JT) over multiple
Transmission Reception Points or panels (TRP): NC-JT refers to MIMO
data transmission over multiple TRPs in which different MIMO layers
are transmitted over different TRPs. An example is shown in FIG. 8,
where data are sent to a UE over two TRPs, each TRP carrying one TB
mapped to one code word. When the UE has 4 receive antennas while
each of the TRPs has only 2 transmit antennas, the UE can support
up to 4 MIMO layers but each TRP can maximally transmit 2 MIMO
layers. In this case, by transmitting data over two TRPs to the UE,
the peak data rate to the UE can be increased as up to 4 aggregated
layers from the two TRPs can be used. This is beneficial when the
traffic load, and thus the resource utilization, is low in each
TRP. In this example, a single scheduler is used to schedule data
over the two TRPs. One PDCCH is transmitted from each of the two
TRPs in a slot, each schedules one PDSCH. This is referred to as a
multi-PDCCH or multi-DCI scheme in which a UE receives two PDCCHs
and the associated two PDSCHs in a slot from two TRPs. The two
PDSCHs are typically allocated with the same time/frequency
resource.
[0105] In another scenario shown in FIG. 9, independent schedulers
are used in each TRP. In this case, only semi-static to
semi-dynamic coordination between the two schedulers can be done
due the non-ideal backhaul, i.e., backhaul with large delay and/or
delay variations which are comparable to the cyclic prefix length
or in some cases even longer, up to several milliseconds.
[0106] In 3GPP RAN1 ad hoc meeting NR_AH_1901, an agreement was
reached that for multi-PDCCH based multi-TRP/panel downlink
transmission for Enhanced Mobile Broad Band (eMBB), separate
ACK/NACK payload/feedback for multiple received PDSCHs is
supported. In addition, it was agreed that for multi-DCI based
multi-TRP/panel transmission, the total number of CWs in scheduled
PDSCHs, each of which is scheduled by one PDCCH, is up to 2, if
resource allocation of PDSCHs are overlapped.
[0107] In 3GPP RAN1 #96, it was agreed that for separate ACK/NACK
payload/feedback for received PDSCHs where multiple DCIs are used,
PUCCH resources conveying ACK/NACK feedback can be Time Domain
Multiplexed (TDMed) with separated HARQ-ACK codebook.
[0108] In RAN1 #96bis, it was further agreed that for separate
ACK/NACK payload/feedbacks for received PDSCHs where multiple DCIs
are used, support would be provided for TDMed PUCCH transmission
within a slot to convey, at least separate ACK/NACK only feedback,
with separated HARQ-ACK codebook for two TRPs.
[0109] In RAN1 #97, it was agreed that for separate ACK/NACK
feedback for PDSCHs received from different TRPs, the UE should be
able to generate separate ACK/NACK codebooks identified by an
index, if the index is configured and applied across all CCs. The
index to be used to generate separated ACK/NACK codebook is a
higher layer signaling index per CORESET. In addition, it was
agreed that joint HARQ-ACK feedback for PDSCHs received from
different TRPs where multiple DCIs are used will also be
supported.
[0110] There currently exist certain challenges. For joint HARQ-ACK
feedback for PDSCHs received from different TRPs where multiple
DCIs are used, there is a need to determine how to construct the
semi-static HARQ codebook. In particular, there is a need to
determine how to multiplex A/N bits associated with two PDSCHs.
SUMMARY
[0111] Systems and methods for joint Hybrid Automatic Repeat
Request (HARQ) feedback for Physical Downlink Shared Channel
(PDSCH) transmission over multiple TRPs are provided. In some
embodiments, a method performed by a wireless device for enabling
transmission feedback includes: receiving a first Transport Block
(TB) and a second TB; and determining the first TB and the second
TB based on a Control Resource Set (CORESET) group identifier of a
CORESET over which a corresponding Downlink Control Information
(DCI) scheduling the TB is received. In this way, the New Radio
(NR) Rel-15 procedure for type 1 HARQ codebook construction might
be reused with the same or minimum increase of HARQ feedback
overhead with semi-static HARQ-ACK codebook.
[0112] In some embodiments, the method also includes, prior to
receiving the first TB and the second TB, receiving a configuration
with a set of PDSCH-to-HARQ-feedback timing, K1, values and/or a
list of PDSCH time domain resource allocations per slot in a
serving cell.
[0113] In some embodiments, the method also includes, prior to
receiving the first TB and the second TB, receiving an indication
to allocate two entries, a first entry and a second entry, in a
type-1 HARQ codebook for each of the configured K1 values and each
set of overlapping PDSCH time domain resource assignments.
[0114] In some embodiments, the method also includes mapping a
HARQ-ACK bit for the first TB to the first entry and a HARQ-ACK bit
for the second TB to the second entry in the Type-1 HARQ-ACK
codebook associated with the same K1 value and the same time domain
resource allocation.
[0115] In some embodiments, the method also includes reporting the
constructed Type-1 HARQ codebook.
[0116] In some embodiments, receiving the first TB and the second
TB comprises receiving in a slot the first TB, from a first
Transmission Reception Point (TRP) and the second TB from a second
TRP, wherein the first and the second TB are scheduled with two
DCIs, one for each TB, and with a same time domain resource
allocation and a same K1 value. In some embodiments, receiving the
indication to allocate two entries can be either explicit or
implicit.
[0117] In some embodiments, receiving the indication to allocate
two entries comprises receiving one or more of the group consisting
of: a higher layer parameter maxNrofCodeWordsScheduledByDCI=2; a
higher layer parameter indicating joint HARQ ACK feedback and a
configuration of two CORESET groups each with a different group
identifier value per CORESET for HARQ-ACK reporting; and a
configuration of one CORESET group each with a same group
identifier value per CORESET for HARQ-ACK reporting.
[0118] In some embodiments, the first or the second entry is filled
with NACK if the first or the second TB is not received,
respectively. In some embodiments, the transmitting may further
comprise transmitting one or two TBs scheduled by a single DCI. In
some embodiments, the first TB corresponds to transport block 1 and
the second TB corresponds to transport block 2 as indicated in the
DCI. In some embodiments, the wireless device is a New Radio (NR)
User Equipment (UE).
[0119] In some embodiments, determining the first TB and the second
TB also includes determining the first TB and the second TB based
on one or more of the group consisting of: a Demodulation Reference
Signal (DMRS) Code Division Multiplexing (CDM) group identifier of
one or more DMRS ports indicated in a corresponding DCI scheduling
the TB; a TB identifier indicated in a corresponding DCI scheduling
the TB; a Transmission Configuration Indication (TCI) state
identifier indicated in a corresponding DCI scheduling the TB; a
TCI state identifier of a CORESET over which a corresponding DCI
scheduling the TB is received; and a scrambling identifier of a
PDSCH carrying the TB.
[0120] In some embodiments, a method performed by a base station
for enabling transmission feedback includes: transmitting, to a
wireless device, a first TB and a second TB, where the first TB and
the second TB are determined based on a CORESET group identifier of
a CORESET over which a corresponding DCI scheduling the TB is
transmitted; and receiving, from the wireless device, a constructed
Type-1 HARQ codebook.
[0121] In some embodiments, the method also includes, prior to
transmitting the first TB and the second TB, transmitting, to the
wireless device, a configuration with a set of
PDSCH-to-HARQ-feedback timing, K1, values and/or a list of PDSCH
time domain resource allocations per slot in a serving cell.
[0122] In some embodiments, the method also includes, prior to
transmitting the first TB and the second TB, transmitting, to the
wireless device, an indication to allocate two entries, a first
entry and a second entry, in a type-1 HARQ codebook for each of the
configured K1 values and each set of overlapping PDSCH time domain
resource assignments.
[0123] In some embodiments, transmitting the first TB and the
second TB comprises transmitting in a slot the first TB, from a
first TRP and the second TB from a second TRP, wherein the first
and the second TB are scheduled with two DCIs, one for each TB, and
with a same time domain resource allocation and a same K1
value.
[0124] In some embodiments, transmitting the indication to allocate
two entries can be either explicit or implicit. In some
embodiments, transmitting the indication to allocate two entries
comprises: transmitting one or more of the group consisting of: a
higher layer parameter maxNrofCodeWordsScheduledByDCI=2; a higher
layer parameter indicating joint HARQ ACK feedback and a
configuration of two CORESET groups each a different group
identifier value per CORESET for HARQ-ACK reporting; a
configuration of one CORESET group each with a same group
identifier value per CORESET for HARQ-ACK reporting.
[0125] In some embodiments, the first or the second entry is filled
with NACK if the first or the second TB is not received,
respectively. In some embodiments, the transmitting may further
comprise transmitting one or two TBs scheduled by a single DCI. In
some embodiments, the first TB corresponds to transport block 1 and
the second TB corresponds to transport block 2 as indicated in the
DCI. In some embodiments, the base station is a NR gNB.
[0126] In some embodiments, the first TB and the second TB are
further determined based on one or more of the group consisting of:
a DMRS CDM group identifier of one or more DMRS ports indicated in
a corresponding DCI scheduling the TB; a TB identifier indicated in
a corresponding DCI scheduling the TB; a TCI state identifier
indicated in a corresponding DCI scheduling the TB; a TCI state
identifier of a CORESET over which a corresponding DCI scheduling
the TB is received; and a scrambling identifier of a PDSCH carrying
the TB.
[0127] In some embodiments, a wireless device for enabling
transmission feedback includes one or more processors and memory.
The memory stores instructions executable by the one or more
processors, whereby the wireless device is operable to perform any
of the methods above.
[0128] In some embodiments, a base station for enabling
transmission feedback includes one or more processors and memory.
The memory stores instructions executable by the one or more
processors, whereby the base station is operable to perform any of
the methods above.
BRIEF DESCRIPTION OF THE DRAWINGS
[0129] The accompanying drawing figures incorporated in and forming
a part of this specification illustrate several aspects of the
disclosure, and together with the description serve to explain the
principles of the disclosure.
[0130] FIG. 1 illustrates a 14-symbol slot, where the first two
symbols contain Physical Downlink Control Channels (PDCCHs) and the
rest contain physical shared data channels, either Physical
Downlink Shared Channels (PDSCHs) or Physical Uplink Shared
Channels (PUSCHs);
[0131] FIG. 2 illustrates a basic New Radio (NR) physical
time-frequency resource grid;
[0132] FIG. 3 shows some examples where two type B PDSCHs are
scheduled in a slot;
[0133] FIG. 4 illustrates NR data transmission over multiple
Multiple-Input-Multiple-Output (MIMO) layers;
[0134] FIG. 5 illustrates mapping of a Demodulation Reference
Signal (DMRS) to resource elements which is configurable in both
frequency and time domain;
[0135] FIG. 6 illustrates a Time Division Duplexing (TDD) pattern
with a set of K1 from 1 to 5 and a configured time-domain resource
allocation table;
[0136] FIG. 7 illustrates a semi-static Hybrid Automatic Repeat
Request (HARQ) codebook for a wireless device configured with three
cells, i.e., cells 1 to 3;
[0137] FIG. 8 illustrates data sent to a wireless device over two
Transmission Reception Points (TRPs), each TRP carrying one TB
mapped to one code word;
[0138] FIG. 9 illustrates independent schedulers are used in each
TRP;
[0139] FIG. 10 illustrates one example of a cellular communications
system in which embodiments of the present disclosure may be
implemented, according to some embodiments of the present
disclosure;
[0140] FIG. 11 illustrates a wireless communication system
represented as a 5G network architecture composed of core Network
Functions (NFs), according to some embodiments of the present
disclosure;
[0141] FIG. 12 illustrates a 5G network architecture using
service-based interfaces between the NFs in the control plane,
instead of the point-to-point reference points/interfaces used in
the 5G network architecture of FIG. 11, according to some
embodiments of the present disclosure;
[0142] FIGS. 13A and 13B illustrate methods of operations of a
wireless device and a base station, respectively, according to some
embodiments of the present disclosure;
[0143] FIG. 13C illustrates a wireless device configured with a K1
range from 1 to 5 which receives either one PDSCH in a slot from
one TRP or two PDSCHs in a slot from two TRPs, according to some
embodiments of the present disclosure;
[0144] FIG. 14 shows an example where PDCCH #1 and PDCCH #2 are
transmitted from TRPs 1 and 2, respectively, according to some
embodiments of the present disclosure;
[0145] FIG. 15 shows an example where PDCCH #1 and PDCCH #2 are
transmitted from TRPs 1 and 2, respectively, according to some
embodiments of the present disclosure;
[0146] FIG. 16 illustrates a CDM group 0 signaled for PDSCH #1 and
CDM group 1 is signaled for PDSCH #2, according to some embodiments
of the present disclosure;
[0147] FIG. 17 illustrates two CORESET groups defined by higher
layer signaling indices, according to some embodiments of the
present disclosure;
[0148] FIG. 18 illustrates a cell configured with one TB and two
CORESET groups, according to some embodiments of the present
disclosure;
[0149] FIG. 19 illustrates one embodiment of a User Equipment (UE),
according to some embodiments of the present disclosure;
[0150] FIG. 20 is a schematic block diagram illustrating a
virtualization environment in which functions implemented by some
embodiments may be virtualized, according to some embodiments of
the present disclosure;
[0151] FIG. 21 illustrates an exemplary communication system,
according to some embodiments of the present disclosure;
[0152] FIG. 22 illustrates example implementations, in accordance
with an embodiment, of the UE, base station, and host computer of
FIG. 21, according to some embodiments of the present
disclosure;
[0153] FIGS. 23 through 26 are flow charts illustrating methods
implemented in a communication system, according to some
embodiments of the present disclosure; and
[0154] FIGS. 27 through 29 depict flowcharts illustrating some
methods implemented in a communication system, according to some
embodiments of the present disclosure.
DETAILED DESCRIPTION
[0155] The embodiments set forth below represent information to
enable those skilled in the art to practice the embodiments and
illustrate the best mode of practicing the embodiments. Upon
reading the following description in light of the accompanying
drawing figures, those skilled in the art will understand the
concepts of the disclosure and will recognize applications of these
concepts not particularly addressed herein. It should be understood
that these concepts and applications fall within the scope of the
disclosure.
[0156] Radio Node: As used herein, a "radio node" is either a radio
access node or a wireless device.
[0157] Radio Access Node: As used herein, a "radio access node" or
"radio network node" is any node in a radio access network of a
cellular communications network that operates to wirelessly
transmit and/or receive signals. Some examples of a radio access
node include, but are not limited to, a base station (e.g., a New
Radio (NR) base station (gNB) in a Third Generation Partnership
Project (3GPP) Fifth Generation (5G) NR network or an enhanced or
evolved Node B (eNB) in a 3GPP Long Term Evolution (LTE) network),
a high-power or macro base station, a low-power base station (e.g.,
a micro base station, a pico base station, a home eNB, or the
like), and a relay node.
[0158] Core Network Node: As used herein, a "core network node" is
any type of node in a core network or any node that implements a
core network function. Some examples of a core network node
include, e.g., a Mobility Management Entity (MME), a Packet Data
Network Gateway (PGW), a Service Capability Exposure Function
(SCEF), a Home Subscriber Server (HSS), or the like. Some other
examples of a core network node include a node implementing a
Access and Mobility Function (AMF), a User Plane Function (UPF), a
Session Management Function (SMF), an Authentication Server
Function (AUSF), a Network Slice Selection Function (NSSF), a
Network Exposure Function (NEF), a Network Function (NF) Repository
Function (NRF), a Policy Control Function (PCF), a Unified Data
Management (UDM), or the like.
[0159] Wireless Device: As used herein, a "wireless device" is any
type of device that has access to (i.e., is served by) a cellular
communications network by wirelessly transmitting and/or receiving
signals to a radio access node(s). Some examples of a wireless
device include, but are not limited to, a User Equipment device
(UE) in a 3GPP network and a Machine Type Communication (MTC)
device.
[0160] Network Node: As used herein, a "network node" is any node
that is either part of the radio access network or the core network
of a cellular communications network/system.
[0161] Note that the description given herein focuses on a 3GPP
cellular communications system and, as such, 3GPP terminology or
terminology similar to 3GPP terminology is oftentimes used.
However, the concepts disclosed herein are not limited to a 3GPP
system.
[0162] Note that, in the description herein, reference may be made
to the term "cell"; however, particularly with respect to 5G NR
concepts, beams may be used instead of cells and, as such, it is
important to note that the concepts described herein are equally
applicable to both cells and beams.
[0163] FIG. 10 illustrates one example of a cellular communications
system 1000 in which embodiments of the present disclosure may be
implemented. In the embodiments described herein, the cellular
communications system 1000 is a 5G system (5GS) including a NR RAN.
In this example, the RAN includes base stations 1002-1 and 1002-2,
which in 5G NR are referred to as gNBs, controlling corresponding
(macro) cells 1004-1 and 1004-2. The base stations 1002-1 and
1002-2 are generally referred to herein collectively as base
stations 1002 and individually as base station 1002. Likewise, the
(macro) cells 1004-1 and 1004-2 are generally referred to herein
collectively as (macro) cells 1004 and individually as (macro) cell
1004. The RAN may also include a number of low power nodes 1006-1
through 1006-4 controlling corresponding small cells 1008-1 through
1008-4. The low power nodes 1006-1 through 1006-4 can be small base
stations (such as pico or femto base stations) or Remote Radio
Heads (RRHs), or the like. Notably, while not illustrated, one or
more of the small cells 1008-1 through 1008-4 may alternatively be
provided by the base stations 1002. The low power nodes 1006-1
through 1006-4 are generally referred to herein collectively as low
power nodes 1006 and individually as low power node 1006. Likewise,
the small cells 1008-1 through 1008-4 are generally referred to
herein collectively as small cells 1008 and individually as small
cell 1008. The cellular communications system 1000 also includes a
core network 1010, which in the 5GS is referred to as the 5G core
(5GC). The base stations 1002 (and optionally the low power nodes
1006) are connected to the core network 1010.
[0164] The base stations 1002 and the low power nodes 1006 provide
service to wireless devices 1012-1 through 1012-5 in the
corresponding cells 1004 and 1008. The wireless devices 1012-1
through 1012-5 are generally referred to herein collectively as
wireless devices 1012 and individually as wireless device 1012. The
wireless devices 1012 are also sometimes referred to herein as
UEs.
[0165] FIG. 11 illustrates a wireless communication system
represented as a 5G network architecture composed of core Network
Functions (NFs), where interaction between any two NFs is
represented by a point-to-point reference point/interface. FIG. 11
can be viewed as one particular implementation of the system 1000
of FIG. 10.
[0166] Seen from the access side the 5G network architecture shown
in FIG. 11 comprises a plurality of User Equipment (UEs) connected
to either a Radio Access Network (RAN) or an Access Network (AN) as
well as an Access and Mobility Management Function (AMF).
Typically, the R(AN) comprises base stations, e.g., such as evolved
Node Bs (eNBs) or 5G base stations (gNBs) or similar. Seen from the
core network side, the 5G core NFs shown in FIG. 11 include a
Network Slice Selection Function (NSSF), an Authentication Server
Function (AUSF), a Unified Data Management (UDM), an AMF, a Session
Management Function (SMF), a Policy Control Function (PCF), and an
Application Function (AF).
[0167] Reference point representations of the 5G network
architecture are used to develop detailed call flows in the
normative standardization. The N1 reference point is defined to
carry signaling between the UE and AMF. The reference points for
connecting between the AN and AMF and between the AN and UPF are
defined as N2 and N3, respectively. There is a reference point,
N11, between the AMF and SMF, which implies that the SMF is at
least partly controlled by the AMF. N4 is used by the SMF and UPF
so that the UPF can be set using the control signal generated by
the SMF, and the UPF can report its state to the SMF. N9 is the
reference point for the connection between different UPFs, and N14
is the reference point connecting between different AMFs,
respectively. N15 and N7 are defined since the PCF applies policy
to the AMF and SMF, respectively. N12 is required for the AMF to
perform authentication of the UE. N8 and N10 are defined because
the subscription data of the UE is required for the AMF and
SMF.
[0168] The 5G core network aims at separating user plane and
control plane. The user plane carries user traffic while the
control plane carries signaling in the network. In FIG. 11, the UPF
is in the user plane and all other NFs, i.e., the AMF, SMF, PCF,
AF, AUSF, and UDM, are in the control plane. Separating the user
and control planes guarantees each plane resource to be scaled
independently. It also allows UPFs to be deployed separately from
control plane functions in a distributed fashion. In this
architecture, UPFs may be deployed very close to UEs to shorten the
Round Trip Time (RTT) between UEs and data network for some
applications requiring low latency.
[0169] The core 5G network architecture is composed of modularized
functions. For example, the AMF and SMF are independent functions
in the control plane. Separated AMF and SMF allow independent
evolution and scaling. Other control plane functions like the PCF
and AUSF can be separated as shown in FIG. 11. Modularized function
design enables the 5G core network to support various services
flexibly.
[0170] Each NF interacts with another NF directly. It is possible
to use intermediate functions to route messages from one NF to
another NF. In the control plane, a set of interactions between two
NFs is defined as service so that its reuse is possible. This
service enables support for modularity. The user plane supports
interactions such as forwarding operations between different
UPFs.
[0171] FIG. 12 illustrates a 5G network architecture using
service-based interfaces between the NFs in the control plane,
instead of the point-to-point reference points/interfaces used in
the 5G network architecture of FIG. 11. However, the NFs described
above with reference to FIG. 11 correspond to the NFs shown in FIG.
12. The service(s) etc. that a NF provides to other authorized NFs
can be exposed to the authorized NFs through the service-based
interface. In FIG. 12 the service based interfaces are indicated by
the letter "N" followed by the name of the NF, e.g., Namf for the
service based interface of the AMF and Nsmf for the service based
interface of the SMF etc. The Network Exposure Function (NEF) and
the Network Function (NF) Repository Function (NRF) in FIG. 12 are
not shown in FIG. 11 discussed above. However, it should be
clarified that all NFs depicted in FIG. 11 can interact with the
NEF and the NRF of FIG. 12 as necessary, though not explicitly
indicated in FIG. 11.
[0172] Some properties of the NFs shown in FIGS. 11 and 12 may be
described in the following manner. The AMF provides UE-based
authentication, authorization, mobility management, etc. A UE even
using multiple access technologies is basically connected to a
single AMF because the AMF is independent of the access
technologies. The SMF is responsible for session management and
allocates Internet Protocol (IP) addresses to UEs. It also selects
and controls the UPF for data transfer. If a UE has multiple
sessions, different SMFs may be allocated to each session to manage
them individually and possibly provide different functionalities
per session. The AF provides information on the packet flow to the
PCF responsible for policy control in order to support Quality of
Service (QoS). Based on the information, the PCF determines
policies about mobility and session management to make the AMF and
SMF operate properly. The AUSF supports authentication function for
UEs or similar and thus stores data for authentication of UEs or
similar while the UDM stores subscription data of the UE. The Data
Network (DN), not part of the 5G core network, provides Internet
access or operator services and similar.
[0173] An NF may be implemented either as a network element on a
dedicated hardware, as a software instance running on a dedicated
hardware, or as a virtualized function instantiated on an
appropriate platform, e.g., a cloud infrastructure.
[0174] In RAN1 #97, it was agreed that for separate ACK/NACK
feedback for Physical Downlink Shared Channels (PDSCHs) received
from different TRPs, the UE should be able to generate separate
ACK/NACK codebooks identified by an index, if the index is
configured and applied across all CCs. The index to be used to
generate separated ACK/NACK codebook is a higher layer signaling
index per Control Resource Set (CORESET). In addition, it was
agreed that joint HARQ-ACK feedback for PDSCHs received from
different TRPs where multiple DCIs are used will also be
supported.
[0175] There currently exist certain challenges. For joint HARQ-ACK
feedback for PDSCHs received from different Transmission Reception
Points (TRPs) where multiple DCIs are used, there is a need to
determine how to construct the semi-static HARQ codebook. In
particular, there is a need to determine how to multiplex A/N bits
associated with two PDSCHs.
[0176] Systems and methods for joint Hybrid Automatic Repeat
Request (HARQ) feedback for PDSCH transmission over multiple TRPs
are provided. In some embodiments, a method performed by a wireless
device for enabling transmission feedback includes: receiving a
first Transport Block (TB) and a second TB; and determining the
first TB and the second TB based on a CORESET group identifier of a
CORESET over which a corresponding Downlink Control Information
(DCI) scheduling the TB is received. In this way, the NR Rel-15
procedure for type 1 HARQ codebook construction might be reused
with the same or minimum increase of HARQ feedback overhead with
semi-static HARQ-ACK codebook.
[0177] FIGS. 13A and 13B illustrate methods of operations of a
wireless device and a base station, respectively, according to some
embodiments of the present disclosure. As shown in FIG. 13A, a
wireless device optionally receives a configuration with a set of
PDSCH-to-HARQ-feedback timing, K1, values and/or a list of PDSCH
time domain resource allocations per slot in a serving cell (step
1300). The wireless device receives a first TB and a second TB
(e.g., in a Component Carrier (CC)) (step 1302). The wireless
device determines the first TB and the second TB based on one or
more indications. As shown in FIG. 13A, the first TB and second TB
are determined based on a CORESET group identifier of a CORESET
over which a corresponding DCI scheduling the TB is received (step
1304). The wireless device optionally reports the constructed
Type-1 HARQ codebook (step 1306). In this way, the NR Rel-15
procedure for type 1 HARQ codebook construction might be reused
with the same or minimum increase of HARQ feedback overhead with
semi-static HARQ-ACK codebook.
[0178] As shown in FIG. 13B, a base station optionally transmits,
to the wireless device, a configuration with a set of
PDSCH-to-HARQ-feedback timing, K1, values and/or a list of PDSCH
time domain resource allocations per slot in a serving cell (step
1308). The base station transmits, to a wireless device, a first TB
and a second TB, where the first TB and the second TB are
determined based on a CORESET group identifier of a CORESET over
which a corresponding DCI scheduling the TB is transmitted (step
1310). The base station receives, from the wireless device, a
constructed Type-1 HARQ codebook (step 1312). In this way, the NR
Rel-15 procedure for type 1 HARQ codebook construction might be
reused with the same or minimum increase of HARQ feedback overhead
with semi-static HARQ-ACK codebook.
[0179] Certain aspects of the present disclosure and their
embodiments may provide solutions to the aforementioned or other
challenges. In some embodiments, a method recognizes that (a) even
with multiple PDCCH scheduling from two TRPs, total 2 TBs can be
scheduled in a slot and/or (b), fully overlapping time domain
resources are used by PDSCHs from the two TRPs. Some embodiments
include:
[0180] In case of implicit joint A/N feedback signaling, a cell
over which joint A/N feedback is to be used is configured with up
to 2 TBs and thus two entries per K1 value and a set of overlapping
TDRA are reserved for semi-static HARQ-ACK codebook for the
cell;
[0181] In case of explicit joint A/N feedback signaling, the number
of entries per K1 value and a set of overlapping TDRA for
Semi-static HARQ-ACK codebook for a cell is determined by the
number of CORESET groups configured in the cell.
[0182] The mapping of an A/N bit for a received TB to one of the
two entries can be according to one of: a DMRS CDM group identifier
of one or more DMRS port indicated in a corresponding DCI
scheduling the TB; a TB identifier indicated in a corresponding DCI
scheduling the TB; a CORESET group identifier of a CORESET over
which a corresponding DCI scheduling the TB is received; a TCI
state identifier indicated in a corresponding DCI scheduling the
TB; a TCI state identifier of a CORESET over which a corresponding
DCI scheduling the TB is received; a scrambling identifier of a
PDSCH carrying the TB.
[0183] A method of Type 1 HARQ-ACK codebook construction for Joint
HARQ ACK reporting with multi-DCI based PDSCH transmissions from
multiple TRPs in a wireless network consisting of at least a
wireless node with two transmission points, TRPs, and at least a
user equipment, UE is described herein. The method comprises:
configuring, by the wireless node, the UE with a set of
PDSCH-to-HARQ-feedback timing, K1, values and a list of PDSCH time
domain resource allocations per slot in a serving cell; and
indicating, by the wireless node, to the UE to allocate two
entries, a first entry and a second entry, in a type-1 HARQ
codebook for each of the configured K1 values and each set of
overlapping PDSCH time domain resource assignments; and
transmitting, by the wireless node, to the UE in a slot a first
transport block, TB, from a first TRP and a second TB from a second
TRP, wherein the first and the second TB are scheduled with two
DCIs, one for each TB, and with a same time domain resource
allocation and a same K1 value; and
[0184] Receiving, by the UE, the first and the second TB; and
determining, by the UE, the first or the second TB based on one or
more of: a DMRS CDM group identifier of one or more DMRS port
indicated in a corresponding DCI scheduling the TB; a TB identifier
indicated in a corresponding DCI scheduling the TB; A CORESET group
identifier of a CORESET over which a corresponding DCI scheduling
the TB is received; a TCI state identifier indicated in a
corresponding DCI scheduling the TB; a TCI state identifier of a
CORESET over which a corresponding DCI scheduling the TB is
received; a scrambling identifier of a PDSCH carrying the TB.
[0185] Mapping, by the UE, a HARQ-ACK bit for the first TB to the
first entry and a HARQ-ACK bit for the second TB to the second
entry in the Type-1 HARQ-ACK codebook associated with the same K1
value and the same time domain resource allocation; and Reporting,
by the UE, the constructed Type-1 HARQ codebook to the wireless
node. The method of 1, wherein the indicating can be either
explicit or implicit by one of: configuring a higher layer
parameter maxNrofCodeWordsScheduledByDCI=2; configuring two CORESET
groups each a different group identifier value per CORESET for
HARQ-ACK reporting.
[0186] The method of 1, wherein the first or the second entry is
filled with NACK if the first or the second TB is not received,
respectively. The method of 1, wherein the transmitting may further
comprise transmitting one or two TBs scheduled by a single DCI. The
methods of 1 and 4, wherein the first TB corresponds to transport
block 1 and the second TB corresponds to transport block 2 as
indicated in the DCI.
[0187] There are, proposed herein, various embodiments which
address one or more of the issues disclosed herein. In some
embodiments, a method performed by a wireless device for providing
transmission feedback includes: receiving a first Transport Block
(TB) and a second TB; and determining the first TB and the second
TB based on one or more of the group consisting of: a Demodulation
Reference Signal (DMRS) Code Division Multiplexing (CDM) group
identifier of one or more DMRS ports indicated in a corresponding
Downlink Control Information (DCI) scheduling the TB; a TB
identifier indicated in a corresponding DCI scheduling the TB; a
Control Resource Set (CORESET) group identifier of a CORESET over
which a corresponding DCI scheduling the TB is received; a TCI
state identifier indicated in a corresponding DCI scheduling the
TB; a TCI state identifier of a CORESET over which a corresponding
DCI scheduling the TB is received; and a scrambling identifier of a
PDSCH carrying the TB.
[0188] Certain embodiments may provide one or more of the following
technical advantage(s). The NR Rel-15 procedure for type 1 HARQ
codebook construction can be reused with the same or minimum
increase of HARQ feedback overhead with semi-static HARQ-ACK
codebook.
[0189] In some embodiments, the method also includes, prior to
receiving the first TB and the second TB: receiving a configuration
with a set of PDSCH-to-HARQ-feedback timing, K1, values and/or a
list of PDSCH time domain resource allocations per slot in a
serving cell.
[0190] In some embodiments, the method also includes, prior to
receiving the first TB and the second TB: receiving an indication
to allocate two entries, a first entry and a second entry, in a
type-1 HARQ codebook for each of the configured K1 values and each
set of overlapping PDSCH time domain resource assignments.
[0191] In some embodiments, the method also includes mapping a
HARQ-ACK bit for the first TB to the first entry and a HARQ-ACK bit
for the second TB to the second entry in the Type-1 HARQ-ACK
codebook associated with the same K1 value and the same time domain
resource allocation. In some embodiments, the method also includes
reporting the constructed Type-1 HARQ codebook.
[0192] In some embodiments, receiving the first TB and the second
TB comprises receiving in a slot the first TB from a first TRP and
the second TB from a second TRP, wherein the first and the second
TB are scheduled with two DCIs, one for each TB, and with a same
time domain resource allocation and a same K1 value.
[0193] In some embodiments, receiving the indication to allocate
two entries can be either explicit or implicit. In some
embodiments, receiving the indication to allocate two entries
comprises: receiving a higher layer parameter
maxNrofCodeWordsScheduledByDCI=2; and/or configuring two CORESET
groups each a different group identifier value per CORESET for
HARQ-ACK reporting.
[0194] In some embodiments, the first or the second entry is filled
with NACK if the first or the second TB is not received,
respectively. In some embodiments, the transmitting may further
comprise transmitting one or two TBs scheduled by a single DCI. In
some embodiments, the first TB corresponds to transport block 1 and
the second TB corresponds to transport block 2 as indicated in the
DCI. In some embodiments, the wireless device is a New Radio (NR)
User Equipment (UE).
[0195] In some embodiments, a method performed by a base station
for receiving transmission feedback includes: transmitting, to a
wireless device, a first TB and a second TB; and receiving, from
the wireless device, a constructed Type-1 HARQ codebook.
[0196] In some embodiments, the method also includes, prior to
transmitting the first TB and the second TB: transmitting, to the
wireless device, a configuration with a set of
PDSCH-to-HARQ-feedback timing, K1, values and/or a list of PDSCH
time domain resource allocations per slot in a serving cell.
[0197] In some embodiments, the method also includes, prior to
transmitting the first TB and the second TB: transmitting, to the
wireless device, an indication to allocate two entries, a first
entry and a second entry, in a type-1 HARQ codebook for each of the
configured K1 values and each set of overlapping PDSCH time domain
resource assignments.
[0198] In some embodiments, transmitting the first TB and the
second TB comprises transmitting in a slot the first TB, from a
first TRP and the second TB from a second TRP, wherein the first
and the second TB are scheduled with two DCIs, one for each TB, and
with a same time domain resource allocation and a same K1
value.
[0199] In some embodiments, transmitting the indication to allocate
two entries can be either explicit or implicit. In some
embodiments, transmitting the indication to allocate two entries
comprises: transmitting a higher layer parameter
maxNrofCodeWordsScheduledByDCI=2; and/or configuring two CORESET
groups each a different group identifier value per CORESET for
HARQ-ACK reporting.
[0200] In some embodiments, the first or the second entry is filled
with NACK if the first or the second TB is not received,
respectively. In some embodiments, the transmitting may further
comprise transmitting one or two TBs scheduled by a single DCI. In
some embodiments, the first TB corresponds to transport block 1 and
the second TB corresponds to transport block 2 as indicated in the
DCI. In some embodiments, the base station is a NR gNB.
[0201] Note that for multiple PDSCH transmission with multiple
PDCCH, the total number of TBs that can be scheduled in a
time-domain resource is two. In other words, only two PDSCHs, each
with one TB, can be scheduled in a slot over a same time domain
resource. If the UE is configured (either explicitly or implicitly)
to use type 1 HARQ-ACK codebook (i.e., semi-static HARQ codebook)
for joint HARQ A/N on a CC, the UE can be configured (either
explicitly or implicitly) with up to two TBs for the CC for type 1
HARQ-ACK codebook construction. If the UE is configured with a
higher layer parameter maxNrofCodeWordsScheduledByDCI=2, there is
no additional signaling needed as two TBs would be assumed for type
1 codebook construction according to the Rel-15 procedure. If the
UE is configured with maxNrofCodeWordsScheduledByDCI=1, then
additional indication/signaling is needed to let the UE know that
two TBs are needed for constructing type 1 HARQ codebook for the
CC.
[0202] An example is shown in FIG. 13C, where a UE is configured
with a K1 range from 1 to 5 and receives either one PDSCH in a slot
from one TRP or two PDSCHs in a slot from two TRPs. A semi-static
HARQ-ACK codebook then consists of five entries each associated
with a K1 value and two rows (note the example in the figure is for
illustration only and the real codebook is a long bit vector
arranged in certain predefined order), each associated with a TB.
In case one PDSCH with two TBs is received in a slot (i.e.,
maxNrofCodeWordsScheduledByDCI=2 is configured), the first row is
associated with TB1 and the second row with TB2, regardless of
which TRP the PDSCH is received from. For example, a PDSCH with two
TBs is received at slot n-5, the corresponding entry in the first
row with K1=5 is associated with TB1 and the corresponding entry in
the second row with K1=5 is associated with TB 2. TB1 and TB2 are
indicated in the corresponding DCI.
[0203] If a PDSCH with one TB is received, whether the TB is
associated with the entry in the first row or the second row can be
determined by the TRP from which the PDSCH is received, e.g., the
first row is associated with TRP1 and the second row with TRP2. For
example, a PDSCH with one TB is received at slot n-4 from TRP1, the
TB is associated with the corresponding entry (K1=4) in the first
row and the entry in the second row is filled with NACK (as there
is no PDSCH received from TRP2). In another example, a PDSCH with
one TB is received at slot n+4 from TRP2, then the TB is associated
with the corresponding entry (K1=1) in the second row and the entry
in the first row is filled with NACK (as there is no PDSCH received
from TRP1).
[0204] If two PDSCHs are received in a slot, e.g., at slots n-3,
n-1, n, n+1, n+3, and n+5, only one TB can be carried by each PDSCH
according to the agreement reached in 3GPP. In this case, the
corresponding entry in the first row is associated with a first TB
(TB 1) received from TRP1 and the corresponding entry in the second
row is associated with a second TB (TB 2) received from TRP2.
However, TRP1 and TRP2 are neither directly signaled to the UE nor
specified in 3GPP specifications. Hence, the first and second TB,
i.e., TB1 and TB2 need to be determined by one or more other
parameters.
[0205] In case no PDSCH is received in a slot, the corresponding
entries in both rows are filled with NACK. For example, no PDSCH is
received in slot n-2, the corresponding entries at K=2 are filled
with NACK.
[0206] With implicit signaling, joint HARQ A/N feedback is used if
the CORESETs where PDCCHs for multi-TRP transmission are received
in a CC have a same higher layer configured index per CORESET
(i.e., a single CORESET group is configured) or are not configured
with a higher layer index per CORESET for multiple PDSCH
transmission with multiple PDCCH. Note that if different higher
layer configured indices are configured for the CORESETs (i.e., two
different CORESET groups are configured), then separate HARQ A/N
feedback is used for multiple PDSCH transmission scheduled by
multiple PDCCH. In this case, the higher layer configured index per
CORESET (which can be used to configure a single CORESET group vs
two CORESET groups) is used to differentiate between using joint
HARQ A/N feedback vs separated HARQ A/N feedback.
[0207] In one embodiment, the UE is configured with
maxNrofCodeWordsScheduledByDCI=2, even though only one TB can be
carried by a PDSCH or the UE is only capable of receiving up to
four DL MIMO layers. In this case, two TB fields are used in DCI
format 1_1 but only one TB is enabled. That is, the first or the
second TB is indicated in the corresponding DCIs. For example, TB1
is mapped to the first row and TB2 is mapped to the second row in
FIG. 13C. A TB is disabled if I.sub.MCS=26 and rv.sub.id=1 for the
corresponding transport block indicated in a DCI.
[0208] If the UE is capable of supporting more than 4 DL MIMO
layers and a DCI is received with two TBs enabled, then the legacy
TB to codeword mapping is used, i.e., TB1 is mapped to the first
row and TB2 to the second row.
[0209] The drawback of the embodiment is that because two TB fields
in DCI format 1-1 are used, there is an increase of DCI overhead if
one TB is always scheduled per PDSCH.
[0210] In another embodiment, joint HARQ ACK feedback with two TBs
per CC may be indicated by configuring a single CORESET group,
i.e., a single RRC configured index value for all CORESETS. In this
case, if maxNrofCodeWordsScheduledByDCI=1 is configured, then only
one TB field is needed in DCI format 1_1 and thus DCI overhead can
be saved. When a PDSCH is received, whether the corresponding TB is
the first or the second TB needs to be determined.
[0211] When the two PDSCHs are transmitted from two TRPs in fully
overlapping time resources, the TCI states indicated in the
corresponding DCIs should be different; the TCI state can be used
to indicate PDSCH 1 or PDSCH 2 (and thus TB1 and TB2,
respectively).
[0212] In NR, the TCI field in DCI can indicate a TCI state (with a
corresponding TCI state ID) that conveys QCL information for the
reception of PDSCH DMRS. FIG. 14 shows an example where PDCCH #1
and PDCCH #2 are transmitted from TRPs 1 and 2, respectively. As
shown in FIG. 14, the DCI corresponding to PDCCH #1 scheduling
PDSCH #1 can indicate one TCI State (e.g., with TCI State ID 3)
while the DCI corresponding to PDCCH #2 scheduling PDSCH #2 can
indicate another TCI State (e.g., with TCI State ID 6). In one
variant of this embodiment, a rule is defined such that if the TCI
State ID indicated in the DCI of a PDCCH is odd, then the TB
corresponding to the PDSCH is the first TB. If the TCI State ID
indicated in the DCI of a PDCCH is even, then the TB corresponding
to the PDSCH is the second TB. Stated more generally, if the TCI
State ID indicated in the DCI of a PDCCH is i, then the TB
corresponding to the PDSCH is the [mod(i,m)].sup.th TB where
m=2.
[0213] In another embodiment, the TCI state activated for PDCCH
that convey QCL information for the reception of PDCCH DMRS is used
to indicate PDSCH 1 or PDSCH 2 (and thus TB 1 and TB 2,
respectively). In NR, a list of TCI States can be configured in a
CORESET and one of the TCI states is activated which provides the
QCL relation for PDCCH DMRS for PDCCHs received in the CORESET.
FIG. 15 shows an example where PDCCH #1 and PDCCH #2 are
transmitted from TRPs 1 and 2, respectively. As shown in FIG. 15,
PDCCH #1 is received in CORESET 1 which has TCI State with ID=3
activated, while PDCCH #2 is received in CORESET 2 which has TCI
State with ID=6 activated. In this embodiment, a rule is defined
such that if the activated TCI State ID corresponding to the
CORESET carrying the PDCCH is odd then the TB corresponding to the
PDSCH scheduled by that PDCCH is the first TB. If the activated TCI
State ID corresponding to the CORESET carrying the PDCCH is even
then the TB corresponding to the PDSCH scheduled by that PDCCH is
the second TB. Stated more generally, if the activated TCI State ID
corresponding to the CORESET carrying the PDCCH is i, then the TB
corresponding to the PDSCH is the [mod(i,m)].sup.th TB where
m=2.
[0214] In addition, different DMRS CDM groups can be used to
indicate PDSCH 1 or PDSCH 2 (and thus TB1 and TB2, respectively).
In one embodiment, the first and the second TB are determined by
the DMRS CDM groups, i.e., the first TB (TB1) is associated with a
PDSCH having CDM group .lamda.=0 and the second TB (TB2) is
associated with a PDSCH having CDM group .lamda.=1 or .lamda.=2. An
example is shown in FIG. 16, where CDM group 0 is signaled for
PDSCH #1 and CDM group 1 is signaled for PDSCH #2. Based on the
embodiment, the first TB (TB 1) is associated with PDSCH #1 while
the second TB (TB 2) is associated with PDSCH #2. The CGM group
number or index can be identified from the DMRS port(s) signaled in
the corresponding DCI.
[0215] For DMRS type 2, there are 3 DMRS CDM groups. Hence, a rule
can be defined such that one of the TBs is associated with a PDSCH
having its DMRS in one CDM group while the other TB is associated
with a PDSCH having its DMRS in one or both of the remaining two
CDM groups. Consider the following example:
[0216] If the DMRS for PDSCH #1 is in CDM group 0, then TB 1 is
associated with PDSCH #1. If the DMRS for PDSCH #2 is in CDM group
1, 2, or both, then TB 2 is associated with PDSCH #2.
[0217] In 3GPP RAN1 #97, it was agreed to introduce multiple PDSCH
scrambling Identities for the case of multiple PDCCH scheduling
multiple PDSCHs. Each PDSCH scrambling identity is used to generate
the PDSCH scrambling sequence for one of the PDSCHs. In one
embodiment, the first and the second TB are determined by the PDSCH
scrambling Identities. For example, if the PDSCH scrambling
identity is odd, then the PDSCH is associated with the first TB. If
the PDSCH scrambling identity is even, then the PDSCH is associated
with the second TB.
[0218] In addition to CDM groups or TCI states of PDSCH other
parameters or characteristics associated with PDSCH, PDCCH, or DCI
conveyed in the DCI can be used to associate a PDSCH with a TB (and
thus the HARQ entry in the codebook). For example, the TCI state of
the scheduling DCI can be used. Alternatively, an explicit bit in
the DCI indicating the TB can be envisioned. A numbering of the
PDCCH candidate within a search space (e.g., based on first CCE
used by PDCCH) can be used to associate the scheduled PDSCH with a
TB.
[0219] If only one PDCCH is received scheduling a PDSCH with two
TBs, the Rel-15 behavior of mapping the TB feedback to positions in
the HARQ codebook is used.
[0220] So far it has been assumed at most one PDSCH from a TRP per
slot is received by the UE. This can be relaxed in a similar way as
in Rel-15: Each of the TRP is associated with a (same or different)
PDSCH time-domain resource allocation table. As in Rel-15, this
table is pruned to remove overlapping entries and PDSCH allocations
overlapping with UL symbol(s). For each entry after pruning, one
HARQ entry is reserved. To extend this principle to multi-TRP, the
combined PDSCH time-domain resource allocation table of both TRPs
is created as the union of the individual time-domain resource
allocation tables. For each element of the union, two entries (one
for each TB) are reserved.
[0221] Joint A/N feedback--explicit signaling: In this embodiment,
it is assumed that a UE is explicitly signaled through higher layer
signaling to use joint HARQ A/N feedback for multiple PDSCH
transmission over multiple TRPs with multiple PDCCH. Each CORESET
is configured with a higher layer configured index. CORESETs with
the same higher layer index forms a CORESET group, the higher layer
index is thus a CORESET group index. Each CORESET group is
associated with one TRP. For two TRPs, two CORESET groups can be
defined by using the higher layer index.
[0222] In this case, when two CORESET groups are configured for a
UE in a CC, 2 TBs are used in type-1 HARQ-ACK codebook construction
for the CC. In this case, if maxNrofCodeWordsScheduledByDCI=1 is
configured, then only one TB field is needed in DCI format 1-1 and
thus DCI overhead can be saved. When two PDSCHs, each carries one
TB and with overlapping TDRA, are received in a slot the first and
the second TB can be determined by the CORESET group index of a
CORESET over which the corresponding PDCCH is received. For
example, the first TB is associated with a PDSCH scheduled by a
PDCCH received in a CORESET with a first CORESET group index while
the second TB is associated with a PDSCH scheduled by a PDCCH
received in a CORESET with a second CORESET group index.
[0223] An example is shown in FIG. 17, where two CORESET groups are
defined by the higher layer signaling indices. Since PDCCH #1 is
received in CORESET 1, which belongs to CORESET group 0, the first
TB (TB 1) is thus associated with PDSCH #1. Similarly, PDCCH #2 is
received in CORESET 3, which belongs to CORESET group 1, the second
TB (TB 2) is then associated with PDSCH #2.
[0224] If maxNrofCodeWordsScheduledByDCI=2 is configured and only
one PDCCH is received scheduling a PDSCH with two codewords, the NR
Rel-15 behavior of mapping the TB feedback to positions in the HARQ
codebook is used. If maxNrofCodeWordsScheduledByDCI=2 is configured
and one PDCCH is received scheduling a PDSCH with one TB enabled,
in one embodiment, the NR Rel-15 behavior of mapping the TB
feedback to positions in the HARQ codebook is used. Alternatively,
the first or the second TB is determined by the CORESET group index
of a CORESET over which the corresponding PDCCH is received.
[0225] If one CORESET group is configured, then the number of TBs
for type-1 HARQ-ACK codebook construction is determined according
to the MIMO configuration maxNrofCodeWordsScheduledByDCI and legacy
NR Rel-15 behavior applies.
[0226] An example is shown in FIG. 18, where the cell is configured
with one TB (i.e., maxNrofCodeWordsScheduledByDCI=1) and two
CORESET groups. The HARQ-ACK codebook consists of two rows (note,
this is for illustration, the real codebook is a long bit vector),
each associated with TBs scheduled by PDCCHs received in one of the
two CORESET groups.
[0227] FIG. 19 is a schematic block diagram of a radio access node
1900 according to some embodiments of the present disclosure. The
radio access node 1900 may be, for example, a base station 1002 or
1006. As illustrated, the radio access node 1900 includes a control
system 1902 that includes one or more processors 1904 (e.g.,
Central Processing Units (CPUs), Application Specific Integrated
Circuits (ASICs), Field Programmable Gate Arrays (FPGAs), and/or
the like), memory 1906, and a network interface 1908. The one or
more processors 1904 are also referred to herein as processing
circuitry. In addition, the radio access node 1900 includes one or
more radio units 1910 that each includes one or more transmitters
1912 and one or more receivers 1914 coupled to one or more antennas
1916. The radio units 1910 may be referred to or be part of radio
interface circuitry. In some embodiments, the radio unit(s) 1910 is
external to the control system 1902 and connected to the control
system 1902 via, e.g., a wired connection (e.g., an optical cable).
However, in some other embodiments, the radio unit(s) 1910 and
potentially the antenna(s) 1916 are integrated together with the
control system 1902. The one or more processors 1904 operate to
provide one or more functions of a radio access node 1900 as
described herein. In some embodiments, the function(s) are
implemented in software that is stored, e.g., in the memory 1906
and executed by the one or more processors 1904.
[0228] FIG. 20 is a schematic block diagram that illustrates a
virtualized embodiment of the radio access node 1900 according to
some embodiments of the present disclosure. This discussion is
equally applicable to other types of network nodes. Further, other
types of network nodes may have similar virtualized
architectures.
[0229] As used herein, a "virtualized" radio access node is an
implementation of the radio access node 1900 in which at least a
portion of the functionality of the radio access node 1900 is
implemented as a virtual component(s) (e.g., via a virtual
machine(s) executing on a physical processing node(s) in a
network(s)). As illustrated, in this example, the radio access node
1900 includes the control system 1902 that includes the one or more
processors 1904 (e.g., CPUs, ASICs, FPGAs, and/or the like), the
memory 1906, and the network interface 1908 and the one or more
radio units 1910 that each includes the one or more transmitters
1912 and the one or more receivers 1914 coupled to the one or more
antennas 1916, as described above. The control system 1902 is
connected to the radio unit(s) 1910 via, for example, an optical
cable or the like. The control system 1902 is connected to one or
more processing nodes 2000 coupled to or included as part of a
network(s) 2002 via the network interface 1908. Each processing
node 2000 includes one or more processors 2004 (e.g., CPUs, ASICs,
FPGAs, and/or the like), memory 2006, and a network interface
2008.
[0230] In this example, functions 2010 of the radio access node
1900 described herein are implemented at the one or more processing
nodes 2000 or distributed across the control system 1902 and the
one or more processing nodes 2000 in any desired manner. In some
particular embodiments, some or all of the functions 2010 of the
radio access node 1900 described herein are implemented as virtual
components executed by one or more virtual machines implemented in
a virtual environment(s) hosted by the processing node(s) 2000. As
will be appreciated by one of ordinary skill in the art, additional
signaling or communication between the processing node(s) 2000 and
the control system 1902 is used in order to carry out at least some
of the desired functions 2010. Notably, in some embodiments, the
control system 1902 may not be included, in which case the radio
unit(s) 1910 communicate directly with the processing node(s) 2000
via an appropriate network interface(s).
[0231] In some embodiments, a computer program including
instructions which, when executed by at least one processor, causes
the at least one processor to carry out the functionality of radio
access node 1900 or a node (e.g., a processing node 2000)
implementing one or more of the functions 2010 of the radio access
node 1900 in a virtual environment according to any of the
embodiments described herein is provided. In some embodiments, a
carrier comprising the aforementioned computer program product is
provided. The carrier is one of an electronic signal, an optical
signal, a radio signal, or a computer readable storage medium
(e.g., a non-transitory computer readable medium such as
memory).
[0232] FIG. 21 is a schematic block diagram of the radio access
node 1900 according to some other embodiments of the present
disclosure. The radio access node 1900 includes one or more modules
2100, each of which is implemented in software. The module(s) 2100
provide the functionality of the radio access node 1900 described
herein. This discussion is equally applicable to the processing
node 2000 of FIG. 20 where the modules 2100 may be implemented at
one of the processing nodes 2000 or distributed across multiple
processing nodes 2000 and/or distributed across the processing
node(s) 2000 and the control system 1902.
[0233] FIG. 22 is a schematic block diagram of a UE 2200 according
to some embodiments of the present disclosure. As illustrated, the
UE 2200 includes one or more processors 2202 (e.g., CPUs, ASICs,
FPGAs, and/or the like), memory 2204, and one or more transceivers
2206 each including one or more transmitters 2208 and one or more
receivers 2210 coupled to one or more antennas 2212. The
transceiver(s) 2206 includes radio-front end circuitry connected to
the antenna(s) 2212 that is configured to condition signals
communicated between the antenna(s) 2212 and the processor(s) 2202,
as will be appreciated by on of ordinary skill in the art. The
processors 2202 are also referred to herein as processing
circuitry. The transceivers 2206 are also referred to herein as
radio circuitry. In some embodiments, the functionality of the UE
2200 described above may be fully or partially implemented in
software that is, e.g., stored in the memory 2204 and executed by
the processor(s) 2202. Note that the UE 2200 may include additional
components not illustrated in FIG. 22 such as, e.g., one or more
user interface components (e.g., an input/output interface
including a display, buttons, a touch screen, a microphone, a
speaker(s), and/or the like and/or any other components for
allowing input of information into the UE 2200 and/or allowing
output of information from the UE 2200), a power supply (e.g., a
battery and associated power circuitry), etc.
[0234] In some embodiments, a computer program including
instructions which, when executed by at least one processor, causes
the at least one processor to carry out the functionality of the UE
2200 according to any of the embodiments described herein is
provided. In some embodiments, a carrier comprising the
aforementioned computer program product is provided. The carrier is
one of an electronic signal, an optical signal, a radio signal, or
a computer readable storage medium (e.g., a non-transitory computer
readable medium such as memory).
[0235] FIG. 23 is a schematic block diagram of the UE 2200
according to some other embodiments of the present disclosure. The
UE 2200 includes one or more modules 2300, each of which is
implemented in software. The module(s) 2300 provide the
functionality of the UE 2200 described herein.
[0236] With reference to FIG. 24, in accordance with an embodiment,
a communication system includes a telecommunication network 2400,
such as a 3GPP-type cellular network, which comprises an access
network 2402, such as a RAN, and a core network 2404. The access
network 2402 comprises a plurality of base stations 2406A, 2406B,
2406C, such as NBs, eNBs, gNBs, or other types of wireless Access
Points (APs), each defining a corresponding coverage area 2408A,
2408B, 2408C. Each base station 2406A, 2406B, 2406C is connectable
to the core network 2404 over a wired or wireless connection 2410.
A first UE 2412 located in coverage area 2408C is configured to
wirelessly connect to, or be paged by, the corresponding base
station 2406C. A second UE 2414 in coverage area 2408A is
wirelessly connectable to the corresponding base station 2406A.
While a plurality of UEs 2412, 2414 are illustrated in this
example, the disclosed embodiments are equally applicable to a
situation where a sole UE is in the coverage area or where a sole
UE is connecting to the corresponding base station 2406.
[0237] The telecommunication network 2400 is itself connected to a
host computer 2416, which may be embodied in the hardware and/or
software of a standalone server, a cloud-implemented server, a
distributed server, or as processing resources in a server farm.
The host computer 2416 may be under the ownership or control of a
service provider, or may be operated by the service provider or on
behalf of the service provider. Connections 2418 and 2420 between
the telecommunication network 2400 and the host computer 2416 may
extend directly from the core network 2404 to the host computer
2416 or may go via an optional intermediate network 2422. The
intermediate network 2422 may be one of, or a combination of more
than one of, a public, private, or hosted network; the intermediate
network 2422, if any, may be a backbone network or the Internet; in
particular, the intermediate network 2422 may comprise two or more
sub-networks (not shown).
[0238] The communication system of FIG. 24 as a whole enables
connectivity between the connected UEs 2412, 2414 and the host
computer 2416. The connectivity may be described as an Over-the-Top
(OTT) connection 2424. The host computer 2416 and the connected UEs
2412, 2414 are configured to communicate data and/or signaling via
the OTT connection 2424, using the access network 2402, the core
network 2404, any intermediate network 2422, and possible further
infrastructure (not shown) as intermediaries. The OTT connection
2424 may be transparent in the sense that the participating
communication devices through which the OTT connection 2424 passes
are unaware of routing of uplink and downlink communications. For
example, the base station 2406 may not or need not be informed
about the past routing of an incoming downlink communication with
data originating from the host computer 2416 to be forwarded (e.g.,
handed over) to a connected UE 2412. Similarly, the base station
2406 need not be aware of the future routing of an outgoing uplink
communication originating from the UE 2412 towards the host
computer 2416.
[0239] Example implementations, in accordance with an embodiment,
of the UE, base station, and host computer discussed in the
preceding paragraphs will now be described with reference to FIG.
25. In a communication system 2500, a host computer 2502 comprises
hardware 2504 including a communication interface 2506 configured
to set up and maintain a wired or wireless connection with an
interface of a different communication device of the communication
system 2500. The host computer 2502 further comprises processing
circuitry 2508, which may have storage and/or processing
capabilities. In particular, the processing circuitry 2508 may
comprise one or more programmable processors, ASICs, FPGAs, or
combinations of these (not shown) adapted to execute instructions.
The host computer 2502 further comprises software 2510, which is
stored in or accessible by the host computer 2502 and executable by
the processing circuitry 2508. The software 2510 includes a host
application 2512. The host application 2512 may be operable to
provide a service to a remote user, such as a UE 2514 connecting
via an OTT connection 2516 terminating at the UE 2514 and the host
computer 2502. In providing the service to the remote user, the
host application 2512 may provide user data which is transmitted
using the OTT connection 2516.
[0240] The communication system 2500 further includes a base
station 2518 provided in a telecommunication system and comprising
hardware 2520 enabling it to communicate with the host computer
2502 and with the UE 2514. The hardware 2520 may include a
communication interface 2522 for setting up and maintaining a wired
or wireless connection with an interface of a different
communication device of the communication system 2500, as well as a
radio interface 2524 for setting up and maintaining at least a
wireless connection 2526 with the UE 2514 located in a coverage
area (not shown in FIG. 25) served by the base station 2518. The
communication interface 2522 may be configured to facilitate a
connection 2528 to the host computer 2502. The connection 2528 may
be direct or it may pass through a core network (not shown in FIG.
25) of the telecommunication system and/or through one or more
intermediate networks outside the telecommunication system. In the
embodiment shown, the hardware 2520 of the base station 2518
further includes processing circuitry 2530, which may comprise one
or more programmable processors, ASICs, FPGAs, or combinations of
these (not shown) adapted to execute instructions. The base station
2518 further has software 2532 stored internally or accessible via
an external connection.
[0241] The communication system 2500 further includes the UE 2514
already referred to. The UE's 2514 hardware 2534 may include a
radio interface 2536 configured to set up and maintain a wireless
connection 2526 with a base station serving a coverage area in
which the UE 2514 is currently located. The hardware 2534 of the UE
2514 further includes processing circuitry 2538, which may comprise
one or more programmable processors, ASICs, FPGAs, or combinations
of these (not shown) adapted to execute instructions. The UE 2514
further comprises software 2540, which is stored in or accessible
by the UE 2514 and executable by the processing circuitry 2538. The
software 2540 includes a client application 2542. The client
application 2542 may be operable to provide a service to a human or
non-human user via the UE 2514, with the support of the host
computer 2502. In the host computer 2502, the executing host
application 2512 may communicate with the executing client
application 2542 via the OTT connection 2516 terminating at the UE
2514 and the host computer 2502. In providing the service to the
user, the client application 2542 may receive request data from the
host application 2512 and provide user data in response to the
request data. The OTT connection 2516 may transfer both the request
data and the user data. The client application 2542 may interact
with the user to generate the user data that it provides.
[0242] It is noted that the host computer 2502, the base station
2518, and the UE 2514 illustrated in FIG. 25 may be similar or
identical to the host computer 2416, one of the base stations
2406A, 2406B, 2406C, and one of the UEs 2412, 2414 of FIG. 24,
respectively. This is to say, the inner workings of these entities
may be as shown in FIG. 25 and independently, the surrounding
network topology may be that of FIG. 24.
[0243] In FIG. 25, the OTT connection 2516 has been drawn
abstractly to illustrate the communication between the host
computer 2502 and the UE 2514 via the base station 2518 without
explicit reference to any intermediary devices and the precise
routing of messages via these devices. The network infrastructure
may determine the routing, which may be configured to hide from the
UE 2514 or from the service provider operating the host computer
2502, or both. While the OTT connection 2516 is active, the network
infrastructure may further take decisions by which it dynamically
changes the routing (e.g., on the basis of load balancing
consideration or reconfiguration of the network).
[0244] The wireless connection 2526 between the UE 2514 and the
base station 2518 is in accordance with the teachings of the
embodiments described throughout this disclosure. One or more of
the various embodiments improve the performance of OTT services
provided to the UE 2514 using the OTT connection 2516, in which the
wireless connection 2526 forms the last segment. More precisely,
the teachings of these embodiments may improve the e.g., data rate,
latency, power consumption, etc. and thereby provide benefits such
as e.g., reduced user waiting time, relaxed restriction on file
size, better responsiveness, extended battery lifetime, etc.
[0245] A measurement procedure may be provided for the purpose of
monitoring data rate, latency, and other factors on which the one
or more embodiments improve. There may further be an optional
network functionality for reconfiguring the OTT connection 2516
between the host computer 2502 and the UE 2514, in response to
variations in the measurement results. The measurement procedure
and/or the network functionality for reconfiguring the OTT
connection 2516 may be implemented in the software 2510 and the
hardware 2504 of the host computer 2502 or in the software 2540 and
the hardware 2534 of the UE 2514, or both. In some embodiments,
sensors (not shown) may be deployed in or in association with
communication devices through which the OTT connection 2516 passes;
the sensors may participate in the measurement procedure by
supplying values of the monitored quantities exemplified above, or
supplying values of other physical quantities from which the
software 2510, 2540 may compute or estimate the monitored
quantities. The reconfiguring of the OTT connection 2516 may
include message format, retransmission settings, preferred routing,
etc.; the reconfiguring need not affect the base station 2518, and
it may be unknown or imperceptible to the base station 2518. Such
procedures and functionalities may be known and practiced in the
art. In certain embodiments, measurements may involve proprietary
UE signaling facilitating the host computer 2502's measurements of
throughput, propagation times, latency, and the like. The
measurements may be implemented in that the software 2510 and 2540
causes messages to be transmitted, in particular empty or `dummy`
messages, using the OTT connection 2516 while it monitors
propagation times, errors, etc.
[0246] FIG. 26 is a flowchart illustrating a method implemented in
a communication system, in accordance with one embodiment. The
communication system includes a host computer, a base station, and
a UE which may be those described with reference to FIGS. 24 and
25. For simplicity of the present disclosure, only drawing
references to FIG. 26 will be included in this section. In step
2600, the host computer provides user data. In sub-step 2602 (which
may be optional) of step 2600, the host computer provides the user
data by executing a host application. In step 2604, the host
computer initiates a transmission carrying the user data to the UE.
In step 2606 (which may be optional), the base station transmits to
the UE the user data which was carried in the transmission that the
host computer initiated, in accordance with the teachings of the
embodiments described throughout this disclosure. In step 2608
(which may also be optional), the UE executes a client application
associated with the host application executed by the host
computer.
[0247] FIG. 27 is a flowchart illustrating a method implemented in
a communication system, in accordance with one embodiment. The
communication system includes a host computer, a base station, and
a UE which may be those described with reference to FIGS. 24 and
25. For simplicity of the present disclosure, only drawing
references to FIG. 27 will be included in this section. In step
2700 of the method, the host computer provides user data. In an
optional sub-step (not shown) the host computer provides the user
data by executing a host application. In step 2702, the host
computer initiates a transmission carrying the user data to the UE.
The transmission may pass via the base station, in accordance with
the teachings of the embodiments described throughout this
disclosure. In step 2704 (which may be optional), the UE receives
the user data carried in the transmission.
[0248] FIG. 28 is a flowchart illustrating a method implemented in
a communication system, in accordance with one embodiment. The
communication system includes a host computer, a base station, and
a UE which may be those described with reference to FIGS. 24 and
25. For simplicity of the present disclosure, only drawing
references to FIG. 28 will be included in this section. In step
2800 (which may be optional), the UE receives input data provided
by the host computer. Additionally or alternatively, in step 2802,
the UE provides user data. In sub-step 2804 (which may be optional)
of step 2800, the UE provides the user data by executing a client
application. In sub-step 2806 (which may be optional) of step 2802,
the UE executes a client application which provides the user data
in reaction to the received input data provided by the host
computer. In providing the user data, the executed client
application may further consider user input received from the user.
Regardless of the specific manner in which the user data was
provided, the UE initiates, in sub-step 2808 (which may be
optional), transmission of the user data to the host computer. In
step 2810 of the method, the host computer receives the user data
transmitted from the UE, in accordance with the teachings of the
embodiments described throughout this disclosure.
[0249] FIG. 29 is a flowchart illustrating a method implemented in
a communication system, in accordance with one embodiment. The
communication system includes a host computer, a base station, and
a UE which may be those described with reference to FIGS. 24 and
25. For simplicity of the present disclosure, only drawing
references to FIG. 29 will be included in this section. In step
2900 (which may be optional), in accordance with the teachings of
the embodiments described throughout this disclosure, the base
station receives user data from the UE. In step 2902 (which may be
optional), the base station initiates transmission of the received
user data to the host computer. In step 2904 (which may be
optional), the host computer receives the user data carried in the
transmission initiated by the base station.
[0250] Any appropriate steps, methods, features, functions, or
benefits disclosed herein may be performed through one or more
functional units or modules of one or more virtual apparatuses.
Each virtual apparatus may comprise a number of these functional
units. These functional units may be implemented via processing
circuitry, which may include one or more microprocessor or
microcontrollers, as well as other digital hardware, which may
include Digital Signal Processor (DSPs), special-purpose digital
logic, and the like. The processing circuitry may be configured to
execute program code stored in memory, which may include one or
several types of memory such as Read Only Memory (ROM), Random
Access Memory (RAM), cache memory, flash memory devices, optical
storage devices, etc. Program code stored in memory includes
program instructions for executing one or more telecommunications
and/or data communications protocols as well as instructions for
carrying out one or more of the techniques described herein. In
some implementations, the processing circuitry may be used to cause
the respective functional unit to perform corresponding functions
according one or more embodiments of the present disclosure.
[0251] While processes in the figures may show a particular order
of operations performed by certain embodiments of the present
disclosure, it should be understood that such order is exemplary
(e.g., alternative embodiments may perform the operations in a
different order, combine certain operations, overlap certain
operations, etc.). Furthermore, throughout the disclosure, the term
"embodiment" can be understood as replaced by the term
"aspect".
EMBODIMENTS
Group A Embodiments
[0252] Embodiment 1: A method performed by a wireless device for
providing transmission feedback, the method comprising: receiving a
first Transport Block, TB, and a second TB; and determining the
first TB and the second TB based on one or more of the group
consisting of: i. a Demodulation Reference Signal, DMRS, Code
Division Multiplexing, CDM, group identifier of one or more DMRS
ports, optionally indicated in a corresponding Downlink Control
Information, DCI, scheduling the TB; ii. a TB identifier,
optionally indicated in a corresponding DCI scheduling the TB; iii.
a Control Resource Set, CORESET, group identifier of a CORESET,
optionally over which a corresponding DCI scheduling the TB is
received; iv. a Transmission Configuration Indication, TCI, state
identifier optionally indicated in a corresponding DCI scheduling
the TB; v. a TCI state identifier of a CORESET optionally over
which a corresponding DCI scheduling the TB is received; and vi. a
scrambling identifier of a Physical Downlink Shared Channel, PDSCH,
carrying the TB.
[0253] Embodiment 2: The method of embodiment 1 further comprising,
prior to receiving the first TB and the second TB: receiving a
configuration with a set of PDSCH-to-Hybrid Automatic Repeat
Request, HARQ-feedback timing, K1, values and/or a list of PDSCH
time domain resource allocations per slot in a serving cell.
[0254] Embodiment 3: The method of any of embodiments 1 to 2
further comprising, prior to receiving the first TB and the second
TB: receiving an indication to allocate two entries, a first entry
and a second entry, in a type-1 HARQ codebook for each of the
configured K1 values and each set of overlapping PDSCH time domain
resource assignments.
[0255] Embodiment 4: The method of any of embodiments 1 to 3
further comprising: mapping a HARQ-ACK bit for the first TB to the
first entry and a HARQ-ACK bit for the second TB to the second
entry in the Type-1 HARQ-ACK codebook associated with the same K1
value and the same time domain resource allocation.
[0256] Embodiment 5: The method of any of embodiments 1 to 4
further comprising: reporting the constructed Type-1 HARQ
codebook.
[0257] Embodiment 6: The method of any of embodiments 1 to 5
wherein receiving the first TB and the second TB comprises
receiving in a slot the first TB, from a first TRP and the second
TB from a second TRP, wherein the first and the second TB are
scheduled with two DCIs, one for each TB, and with a same time
domain resource allocation and a same K1 value.
[0258] Embodiment 7: The method of any of embodiments 3 to 6
wherein receiving the indication to allocate two entries can be
either explicitly or implicitly.
[0259] Embodiment 8: The method of embodiment 7 wherein receiving
the indication to allocate two entries comprises: receiving one or
more of: a. a higher layer parameter
maxNrofCodeWordsScheduledByDCI=2; b. a higher layer parameter
indicating joint HARQ Ack feedback and a configuration of two
CORESET groups each with a different group identifier value per
CORESET for HARQ-Ack reporting; c. a configuration of one CORESET
group each with a same group identifier value per CORESET for
HARQ-Ack reporting.
[0260] Embodiment 9: The method of any of embodiments 1 to 8
wherein the first or the second entry is filled with NACK if the
first or the second TB is not received, respectively.
[0261] Embodiment 10: The method of any of embodiments 1 to 9
wherein the transmitting may further comprise transmitting one or
two TBs scheduled by a single DCI.
[0262] Embodiment 11: The method of any of embodiments 1 to 10
wherein the first TB corresponds to transport block 1 and the
second TB corresponds to transport block 2 as indicated in the
DCI.
[0263] Embodiment 12: The method of any of embodiments 1 to 11
wherein the wireless device is a New Radio, NR, User Equipment,
UE.
[0264] Embodiment 13: The method of any of the previous
embodiments, further comprising: providing user data; and
forwarding the user data to a host computer via the transmission to
the base station.
Group B Embodiments
[0265] Embodiment 14: A method performed by a base station for
receiving transmission feedback, the method comprising:
transmitting, to a wireless device, a first Transport Block, TB,
and a second TB; and receiving, from the wireless device, a
constructed Type-1 Hybrid Automatic Repeat Request, HARQ,
codebook.
[0266] Embodiment 15: The method of embodiment 14 further
comprising, prior to transmitting the first TB and the second TB:
transmitting, to the wireless device, a configuration with a set of
PDSCH-to-HARQ-feedback timing, K1, values and/or a list of PDSCH
time domain resource allocations per slot in a serving cell.
[0267] Embodiment 16: The method of any of embodiments 14 to 15
further comprising, prior to transmitting the first TB and the
second TB: transmitting, to the wireless device, an indication to
allocate two entries, a first entry and a second entry, in a type-1
HARQ codebook for each of the configured K1 values and each set of
overlapping PDSCH time domain resource assignments.
[0268] Embodiment 17: The method of any of embodiments 14 to 16
wherein transmitting the first TB and the second TB comprises
transmitting in a slot the first TB, from a first TRP and the
second TB from a second TRP, wherein the first and the second TB
are scheduled with two DCIs, one for each TB, and with a same time
domain resource allocation and a same K1 value.
[0269] Embodiment 18: The method of any of embodiments 14 to 17
wherein transmitting the indication to allocate two entries can be
either explicitly or implicitly.
[0270] Embodiment 19: The method of embodiment 18 wherein
transmitting the indication to allocate two entries comprises:
transmitting one or more of: a. a higher layer parameter
maxNrofCodeWordsScheduledByDCI=2; b. a higher layer parameter
indicating joint HARQ Ack feedback and a configuration of two
CORESET groups each a different group identifier value per CORESET
for HARQ-Ack reporting; c. a configuration of one CORESET group
each with a same group identifier value per CORESET for HARQ-Ack
reporting.
[0271] Embodiment 20: The method of any of embodiments 14 to 19
wherein the first or the second entry is filled with NACK if the
first or the second TB is not received, respectively.
[0272] Embodiment 21: The method of any of embodiments 14 to 20
wherein the transmitting may further comprise transmitting one or
two TBs scheduled by a single DCI.
[0273] Embodiment 22: The method of any of embodiments 14 to 21
wherein the first TB corresponds to transport block 1 and the
second TB corresponds to transport block 2 as indicated in the
DCI.
[0274] Embodiment 23: The method of any of embodiments 14 to 22
wherein the base station is a New Radio, NR, gNB.
[0275] Embodiment 24: The method of any of the previous
embodiments, further comprising: obtaining user data; and
forwarding the user data to a host computer or a wireless
device.
Group C Embodiments
[0276] Embodiment 25: A wireless device for providing transmission
feedback, the wireless device comprising: processing circuitry
configured to perform any of the steps of any of the Group A
embodiments; and power supply circuitry configured to supply power
to the wireless device.
[0277] Embodiment 26: A base station for receiving transmission
feedback, the base station comprising: processing circuitry
configured to perform any of the steps of any of the Group B
embodiments; and power supply circuitry configured to supply power
to the base station.
[0278] Embodiment 27: A User Equipment, UE, for providing
transmission feedback, the UE comprising: an antenna configured to
send and receive wireless signals; radio front-end circuitry
connected to the antenna and to processing circuitry, and
configured to condition signals communicated between the antenna
and the processing circuitry; the processing circuitry being
configured to perform any of the steps of any of the Group A
embodiments; an input interface connected to the processing
circuitry and configured to allow input of information into the UE
to be processed by the processing circuitry; an output interface
connected to the processing circuitry and configured to output
information from the UE that has been processed by the processing
circuitry; and a battery connected to the processing circuitry and
configured to supply power to the UE.
[0279] Embodiment 28: A communication system including a host
computer comprising: processing circuitry configured to provide
user data; and a communication interface configured to forward the
user data to a cellular network for transmission to a User
Equipment, UE; wherein the cellular network comprises a base
station having a radio interface and processing circuitry, the base
station's processing circuitry configured to perform any of the
steps of any of the Group B embodiments.
[0280] Embodiment 29: The communication system of the previous
embodiment further including the base station.
[0281] Embodiment 30: The communication system of the previous 2
embodiments, further including the UE, wherein the UE is configured
to communicate with the base station.
[0282] Embodiment 31: The communication system of the previous 3
embodiments, wherein: the processing circuitry of the host computer
is configured to execute a host application, thereby providing the
user data; and the UE comprises processing circuitry configured to
execute a client application associated with the host
application.
[0283] Embodiment 32: A method implemented in a communication
system including a host computer, a base station, and a User
Equipment, UE, the method comprising: at the host computer,
providing user data; and at the host computer, initiating a
transmission carrying the user data to the UE via a cellular
network comprising the base station, wherein the base station
performs any of the steps of any of the Group B embodiments.
[0284] Embodiment 33: The method of the previous embodiment,
further comprising, at the base station, transmitting the user
data.
[0285] Embodiment 34: The method of the previous 2 embodiments,
wherein the user data is provided at the host computer by executing
a host application, the method further comprising, at the UE,
executing a client application associated with the host
application.
[0286] Embodiment 35: A User Equipment, UE, configured to
communicate with a base station, the UE comprising a radio
interface and processing circuitry configured to perform the method
of the previous 3 embodiments.
[0287] Embodiment 36: A communication system including a host
computer comprising: processing circuitry configured to provide
user data; and a communication interface configured to forward user
data to a cellular network for transmission to a User Equipment,
UE; wherein the UE comprises a radio interface and processing
circuitry, the UE's components configured to perform any of the
steps of any of the Group A embodiments.
[0288] Embodiment 37: The communication system of the previous
embodiment, wherein the cellular network further includes a base
station configured to communicate with the UE.
[0289] Embodiment 38: The communication system of the previous 2
embodiments, wherein: the processing circuitry of the host computer
is configured to execute a host application, thereby providing the
user data; and the UE's processing circuitry is configured to
execute a client application associated with the host
application.
[0290] Embodiment 39: A method implemented in a communication
system including a host computer, a base station, and a User
Equipment, UE, the method comprising: at the host computer,
providing user data; and at the host computer, initiating a
transmission carrying the user data to the UE via a cellular
network comprising the base station, wherein the UE performs any of
the steps of any of the Group A embodiments.
[0291] Embodiment 40: The method of the previous embodiment,
further comprising at the UE, receiving the user data from the base
station.
[0292] Embodiment 41: A communication system including a host
computer comprising: communication interface configured to receive
user data originating from a transmission from a User Equipment,
UE, to a base station; wherein the UE comprises a radio interface
and processing circuitry, the UE's processing circuitry configured
to perform any of the steps of any of the Group A embodiments.
[0293] Embodiment 42: The communication system of the previous
embodiment, further including the UE.
[0294] Embodiment 43: The communication system of the previous 2
embodiments, further including the base station, wherein the base
station comprises a radio interface configured to communicate with
the UE and a communication interface configured to forward to the
host computer the user data carried by a transmission from the UE
to the base station.
[0295] Embodiment 44: The communication system of the previous 3
embodiments, wherein: the processing circuitry of the host computer
is configured to execute a host application; and the UE's
processing circuitry is configured to execute a client application
associated with the host application, thereby providing the user
data.
[0296] Embodiment 45: The communication system of the previous 4
embodiments, wherein: the processing circuitry of the host computer
is configured to execute a host application, thereby providing
request data; and the UE's processing circuitry is configured to
execute a client application associated with the host application,
thereby providing the user data in response to the request
data.
[0297] Embodiment 46: A method implemented in a communication
system including a host computer, a base station, and a User
Equipment, UE, the method comprising: at the host computer,
receiving user data transmitted to the base station from the UE,
wherein the UE performs any of the steps of any of the Group A
embodiments.
[0298] Embodiment 47: The method of the previous embodiment,
further comprising, at the UE, providing the user data to the base
station.
[0299] Embodiment 48: The method of the previous 2 embodiments,
further comprising: at the UE, executing a client application,
thereby providing the user data to be transmitted; and at the host
computer, executing a host application associated with the client
application.
[0300] Embodiment 49: The method of the previous 3 embodiments,
further comprising: at the UE, executing a client application; and
at the UE, receiving input data to the client application, the
input data being provided at the host computer by executing a host
application associated with the client application; wherein the
user data to be transmitted is provided by the client application
in response to the input data.
[0301] Embodiment 50: A communication system including a host
computer comprising a communication interface configured to receive
user data originating from a transmission from a User Equipment,
UE, to a base station, wherein the base station comprises a radio
interface and processing circuitry, the base station's processing
circuitry configured to perform any of the steps of any of the
Group B embodiments.
[0302] Embodiment 51: The communication system of the previous
embodiment further including the base station.
[0303] Embodiment 52: The communication system of the previous 2
embodiments, further including the UE, wherein the UE is configured
to communicate with the base station.
[0304] Embodiment 53: The communication system of the previous 3
embodiments, wherein: the processing circuitry of the host computer
is configured to execute a host application; and the UE is
configured to execute a client application associated with the host
application, thereby providing the user data to be received by the
host computer.
[0305] Embodiment 54: A method implemented in a communication
system including a host computer, a base station, and a User
Equipment, UE, the method comprising: at the host computer,
receiving, from the base station, user data originating from a
transmission which the base station has received from the UE,
wherein the UE performs any of the steps of any of the Group A
embodiments.
[0306] Embodiment 55: The method of the previous embodiment,
further comprising at the base station, receiving the user data
from the UE.
[0307] Embodiment 56: The method of the previous 2 embodiments,
further comprising at the base station, initiating a transmission
of the received user data to the host computer.
[0308] At least some of the following abbreviations may be used in
this disclosure. If there is an inconsistency between
abbreviations, preference should be given to how it is used above.
If listed multiple times below, the first listing should be
preferred over any subsequent listing(s). [0309] 3GPP Third
Generation Partnership Project [0310] 5G Fifth Generation [0311]
5GC Fifth Generation Core [0312] 5GS Fifth Generation System [0313]
ACK Acknowledgement [0314] AF Application Function [0315] AMF
Access and Mobility Function [0316] AN Access Network [0317] AP
Access Point [0318] ASIC Application Specific Integrated Circuit
[0319] AUSF Authentication Server Function [0320] CA Carrier
Aggregation [0321] CBG Code Block Group [0322] CC Component Carrier
[0323] CCE Control Channel Element [0324] CDM Code Division
Multiplexing [0325] CORESET Control Resource Set [0326] CP-OFDM
Cyclic Prefix-Orthogonal Frequency Division Multiplexing [0327] CPU
Central Processing Unit [0328] CRC Cyclic Redundancy Check [0329]
C-RNTI Cell-Radio Network Temporary Identifier [0330] CSI-RS
Channel State Information Reference Signal [0331] CS-RNTI
Configured Scheduling-Radio Network Temporary Identifier [0332] CSS
Common Search Space [0333] CW Codeword [0334] DAI Downlink
Assignment Index [0335] DCI Downlink Control Information [0336] DFT
Discrete Fourier Transform [0337] DL Downlink [0338] DMRS
Demodulation Reference Signal [0339] DN Data Network [0340] DSP
Digital Signal Processor [0341] eMBB Enhanced Mobile Broadband
[0342] eNB Enhanced or Evolved Node B [0343] FPGA Field
Programmable Gate Array [0344] FR Frequency Range [0345] gNB New
Radio Base Station [0346] HARQ Hybrid Automatic Repeat Request
[0347] HSS Home Subscriber Server [0348] IE Information Element
[0349] IP Internet Protocol [0350] LTE Long Term Evolution [0351]
MCS Modulation and Coding Scheme [0352] MIMO Multiple Input
Multiple Output [0353] MME Mobility Management Entity [0354] MTC
Machine Type Communication [0355] NC-JT Non-Coherent Joint
Transmission [0356] NDI New Data Indicator [0357] NEF Network
Exposure Function [0358] NF Network Function [0359] NR New Radio
[0360] NRF Network Function Repository Function [0361] NSSF Network
Slice Selection Function [0362] OTT Over-the-Top [0363] PCF Policy
Control Function [0364] PDCCH Physical Downlink Control Channel
[0365] PDSCH Physical Downlink Shared Channel [0366] P-GW Packet
Data Network Gateway [0367] PRB Physical Resource Block [0368] PRI
PUCCH Resource Indicator [0369] PUCCH Physical Uplink Control
Channel [0370] PUSCH Physical Uplink Shared Channel [0371] QCL
Quasi Co-Located [0372] QoS Quality of Service [0373] RAM Random
Access Memory [0374] RAN Radio Access Network [0375] RB Resource
Block [0376] RE Resource Element [0377] REG Resource Element Group
[0378] ROM Read Only Memory [0379] RRC Radio Resource Control
[0380] RRH Remote Radio Head [0381] RTT Round Trip Time [0382] SCEF
Service Capability Exposure Function [0383] SINR Signal to
Interference Plus Noise Ratio [0384] SMF Session Management
Function [0385] SR Scheduling Request [0386] SSB Synchronization
Signal Block [0387] TB Transport Block [0388] TCI Transmission
Configuration Indication [0389] TDD Time Division Duplexing [0390]
TDM Time Division Multiplexing [0391] TDRA Time Domain Resource
Assignment [0392] TPC Transmit Power Control [0393] TRP
Transmission Reception Point [0394] TRS Tracking Reference Signal
[0395] UCI Uplink Control Information [0396] UDM Unified Data
Management [0397] UE User Equipment [0398] UL Uplink [0399] UPF
User Plane Function [0400] USS UE Specific Search Space [0401] VRB
Virtual Resource Block [0402] ZP Zero Power
[0403] Those skilled in the art will recognize improvements and
modifications to the embodiments of the present disclosure. All
such improvements and modifications are considered within the scope
of the concepts disclosed herein.
* * * * *